It's Not Enough to Prove They Got It Wrong: How the Materiality Threshold Expanded Beyond Errors of Law
Where We Left Off
Before Hossain, the law was messy. Courts had been wrestling with the same question for decades: when a decision-maker makes a legal error, does that automatically invalidate the decision? The old approach — inherited from Project Blue Sky Inc v Australian Broadcasting Authority (1998) 194 CLR 355 — asked whether Parliament intended the relevant statutory requirement to be "mandatory" or "directory." If it was mandatory, a breach meant the decision was invalid. End of story.
Hossain rewrote that formula. The High Court said: forget the mandatory/directory distinction. Instead, ask whether the error was material. Could compliance with the law realistically have led to a different outcome? If the answer is no — if the decision would have been the same regardless of the error — then there is no jurisdictional error. No jurisdictional error means no remedy. The decision stands.
But Hossain was about a specific kind of error: a legal error on a visa criterion. The Tribunal had asked itself the wrong legal question about a debt owed to the Commonwealth. That was a mistake of law — a wrong turn in legal reasoning.
What about other types of error? What happens when the decision-maker breaches the rules of procedural fairness — the fundamental requirement that a person be given a fair hearing before an adverse decision is made? What about when the decision-maker ignores something they were legally required to consider — a mandatory relevant consideration?
Those questions came next. And the answers, delivered in two further High Court decisions, were not good news for applicants.
SZMTA: When the Tribunal Hides Things From You — But It "Doesn't Matter"
The Background
Minister for Immigration and Border Protection v SZMTA [2019] HCA 3; (2019) 264 CLR 421 was actually three appeals heard together. Each involved protection visa applicants — people who had asked Australia for protection because they feared persecution in their home countries. In each case, a delegate of the Minister had refused the visa, and the applicant had applied to the Refugee Review Tribunal (under Part 7 of the Migration Act 1958) for merits review.
Here is where the story gets interesting.
When the Department sends documents to the Tribunal for the purpose of a review, the Secretary sometimes notifies the Tribunal that section 438 of the Migration Act applies to certain material. Section 438 deals with documents or information that were given to the Department in confidence, or where the Minister has certified that disclosure would be contrary to the public interest. When a s 438 notification is made, the Tribunal gets a choice: it can look at the material, and it can decide whether or not to show it to the applicant.
The critical point is this: the Tribunal has a discretion. It might look at adverse information about you and decide not to share it. It might use that information against you without you ever knowing it existed.
What Went Wrong
In SZMTA and the companion cases, the Secretary of the Department sent s 438 notifications to the Tribunal. The problem? The Tribunal never told the applicants that the notifications existed. The applicants had no idea that documents about them had been flagged as confidential, no idea what those documents contained, and no opportunity to respond to whatever was in them.
The High Court was unanimous on one point: when a Tribunal receives a s 438 notification, procedural fairness requires the Tribunal to at least tell the applicant that the notification has been made. Not telling the applicant at all — keeping the very existence of the notification secret — is a breach of the requirement to give a person a fair hearing. Everyone on the bench agreed about that.
But here is where the Court split, and where it mattered.
The Key Question
The real question was not whether the Tribunal had done something wrong. It plainly had. The question was: so what?
Did the breach of procedural fairness amount to a jurisdictional error — the type of legal error that would allow a court to set the decision aside? Or was it the kind of error that, while regrettable, did not actually affect the outcome?
The Majority's Answer
The majority — Justices Bell, Gageler, and Keane — applied the materiality framework from Hossain. They held that a breach of a statutory procedural fairness requirement is only a jurisdictional error if the breach is material.
What does material mean in this context? The breach must have "deprived the applicant of the possibility of a successful outcome." In other words, the applicant has to show that if the Tribunal had done the right thing — if it had told the applicant about the s 438 notification — there is a realistic possibility that the Tribunal's decision could have been different.
And here is the part that stings: the onus of proving that a realistic possibility falls on the applicant. You are the one who has to demonstrate that the breach mattered. The government does not have to prove that it didn't.
The majority found that in the SZMTA cases, the denial of procedural fairness could not realistically have made any difference to the result. The notifications were either incorrect or inconsequential. Even if the applicants had been told about them and given a chance to respond, the outcome would have been the same. Appeal allowed. Decisions upheld.
The Dissent
Justices Nettle and Gordon strongly disagreed — not with the outcome, but with the entire concept of materiality as a precondition to jurisdictional error. Their Honours said that the law either requires something or it does not. If a decision-maker breaches a condition imposed by the law, the decision is invalid. Full stop. You do not get to say "yes, they broke the rules, but it didn't matter, so we'll let it stand."
As their Honours put it, a decision "cannot be a little bit invalid or a little bit beyond power." If it is beyond power, it is beyond power.
But Nettle and Gordon JJ were in the minority. The majority's view — that materiality is essential to the existence of jurisdictional error, including for breaches of procedural fairness — became law.
What This Meant in Practice
Think about what this means for someone who has been denied a fair hearing. Before SZMTA, if you could show the Tribunal hid something from you, you had a strong argument for getting the decision thrown out. The law required the Tribunal to give you a fair hearing. The Tribunal didn't. That should be enough.
After SZMTA, it is not enough. You have to go a step further. You have to persuade the court that if you had been given a fair hearing, there is a realistic chance the outcome would have been different.
That is an extraordinarily difficult thing to prove, especially when the whole point of your complaint is that you never got the chance to see the material and respond to it. You are, in effect, being asked to demonstrate what you would have said in response to something you were never shown — and to persuade a court that what you would have said could have changed the Tribunal's mind. The circularity is obvious, and it is brutal.
MZAPC: Proving the Unprovable — The Materiality Onus Gets Teeth
The Facts
MZAPC v Minister for Immigration and Border Protection [2021] HCA 17; (2021) 95 ALJR 441 arrived at the High Court two years after SZMTA. The facts were remarkably similar — which was no coincidence. The Court was being asked to revisit and refine the materiality framework it had just created.
MZAPC was a citizen of India who arrived in Australia on a student visa in 2006. His student visa expired in 2008, but before that happened he had applied for a further student visa, which a delegate of the Minister refused in 2012. After that refusal, he eventually applied for a protection visa, claiming he feared being killed by his uncle in a dispute over land in Punjab.
A delegate of the Minister refused the protection visa in 2014. MZAPC then applied to the Refugee Review Tribunal for merits review.
Here is where the familiar pattern repeats. The Secretary of the Department sent documents to the Tribunal, including a "Court Outcomes Report" that revealed MZAPC had been convicted of several offences in Australia — among them, the offence of stating a false name to police. The Secretary issued a s 438 notification in relation to these documents. And — just as in SZMTA — the Tribunal never told MZAPC that the notification existed.
The Tribunal refused the protection visa. Its reasons focused entirely on the plausibility of MZAPC's claim that he would be persecuted over the land dispute. The Tribunal's decision made no reference whatsoever to the criminal record documents, no reference to the s 438 notification, and gave no indication that those materials played any part in the decision. Apart from a boilerplate statement that it had considered "all the circumstances," there was nothing to suggest the criminal record mattered.
Everyone agreed that the failure to disclose the notification was a breach of procedural fairness — the same type of breach identified in SZMTA. The only issue was whether the breach was material.
The Argument
MZAPC's argument was clever. He said: look, my criminal record included a dishonesty offence. If the Tribunal had told me about the notification, I could have explained the circumstances of those convictions. More importantly, if the Tribunal was using my criminal record — even subconsciously — to assess my credibility, the dishonesty conviction could have coloured the Tribunal's view of whether I was telling the truth about the land dispute. I should have had the chance to address that.
He also argued that the onus of proof was wrong. He said that once he showed the Tribunal could have taken the information into account adversely, the onus should shift to the Minister to prove it didn't. He should not have to prove a negative.
The High Court's Decision
The High Court unanimously dismissed the appeal — but, characteristically, for different reasons.
The majority (Kiefel CJ, Gageler, Keane, and Gleeson JJ) confirmed that the onus of proving materiality lies squarely on the applicant. You bear the burden of proving, on the balance of probabilities, the historical facts necessary to satisfy the court that the decision could realistically have been different.
In MZAPC's case, this meant he had to first establish that the Tribunal had actually taken the criminal record into account. After all, if the Tribunal never looked at the criminal record material at all, then the failure to tell MZAPC about it could not have mattered — there was nothing for MZAPC to respond to.
And here is where MZAPC's case fell apart. The Tribunal's reasons said nothing about the criminal record. There was no eviden the Tribunal had considered it. Without proving that the Tribunal actually used the material, MZAPC could not establish that the breach of procedural fairness was material.
The majority acknowledged that there might be cases where prejudicial information is "so highly prejudicial" that a fair-minded observer would not dismiss the possibility that the Tribunal was affected by it subconsciously, even without any reference to it in the reasons. But this was not such a case. A conviction for stating a false name simply was not so explosive that it would inevitably taint the Tribunal's thinking.
Gordon and Steward JJ agreed the appeal should be dismissed but disagreed about the onus. Their Honours held that once the applicant clears the low threshold of showing a realistic possibility that the error affected the decision, the onus should shift to the government to prove that it didn't. Edelman J, in separate reasons, similarly held that the applicant's burden should be minimal — merely showing a "threshold requirement of injustice" — with the heavier burden falling on the state.
But these were minority positions. The majority's approach — applicant bears the full onus throughout — is the law.
The Limits of Materiality: A Crucial Carve-Out
MZAPC also delivered an important qualification. The majority, at [33], confirmed that the materiality threshold does not apply to every type of jurisdictional error. There are conditions implied into statutory decision-making that, "of their nature, incorporate an element of materiality" and are inherently jurisdictional when breached. The majority identified two examples:
Bias: If the decision-maker was biased (or there was an apprehension of bias), that is a jurisdictional error. You do not have to prove the bias changed the outcome.
Legal unreasonableness: If the decision was so unreasonable that no reasonable decision-maker could have reached it, that is a jurisdictional error. You do not need to show that a different decision was realistically possible — the unreasonableness is the error.
This is an important boundary. But for the three most commonly litigated categories of error — errors of law, breaches of procedural fairness, and failure to consider mandatory relevant considerations — materiality applies in full.
The Peko-Wallsend Thread: Mandatory Relevant Considerations
This is the right place to address the third pillar.
Long before Hossain, the High Court in Minister for Aboriginal Affairs v Peko-Wallsend Ltd [1986] HCA 40; (1986) 162 CLR 24 established the framework for mandatory relevant considerations. Mason J held that a decision-maker's failure to consider a matter they were legally bound to consider could amount to a reviewable error — but also observed that some mandatory considerations might be "so insignificant that the failure to take it into account could not have materially affected the decision."
That observation sat in the law for decades, doing relatively modest work. Then Hossain picked it up.
In Hossain, at [30], the plurality expressly cited Mason J's language from Peko-Wallsend as an example of the materiality threshold in action. The threshold, said the plurality, "would not ordinarily be met, for example, ... where a decision-maker failed to take into account a mandatory consideration which in all the circumstances was 'so insignificant that the failure to take it into account could not have materially affected' the decision that was made."
And in MZAPC, the majority's confirmation that materiality applies across all categories of error except bias and unreasonableness cemented this position. The result is that the old Peko-Wallsend "so insignificant" qualification has been absorbed into the broader Hossain materiality framework.
What does this mean in practice? If a decision-maker ignores something they were required by law to consider — say, a specific piece of country information in a protection visa case, or a particular factor in a character decision — that failure is only a jurisdictional error if the ignored material could realistically have changed the outcome. If the ignored consideration was relatively minor, or if the case against you was overwhelming on other grounds, the failure to consider it will not help you.
The Cumulative Effect: Hossain + SZMTA + MZAPC
Stand back and look at what the trilogy has done.
Before these three cases, Australian immigration law had three well-established categories of error that could form a judicial review challenge:
Errors of law — the decision-maker applied the wrong legal test or misunderstood the law.
Breaches of procedural fairness — the decision-maker denied the applicant a fair hearing.
Failure to consider mandatory relevant considerations — the decision-maker ignored something they were legally required to consider.
Each of these categories was, in its own right, a pathway to having a decision set aside. If you could show the error, you were entitled to relief (subject to discretionary considerations).
Now, after the trilogy:
Hossain (2018) applied the materiality threshold to errors of law.
SZMTA (2019) extended it to breaches of procedural fairness.
Hossain (at [30], through Peko-Wallsend) and MZAPC (2021, confirming the broad application) captured mandatory relevant considerations.
The result is a significant contraction in the availability of relief. Across all three categories, the same test now applies: the error must be material — it must have deprived the applicant of a realistic possibility of a different outcome. And the applicant carries the onus of proving that.
The only exceptions are bias and legal unreasonableness, which are inherently jurisdictional.
What This Means for You — Right Now
If you are reading this because you received an adverse visa decision and you are thinking about challenging it in court, here is the reality you face.
It is not enough to show the decision-maker got it wrong. It used to be. It isn't anymore. You now have to show that the error mattered — that if the decision-maker had not made the mistake, there is a realistic chance the outcome would have been different.
You carry the burden of proof. The government does not have to prove that the error was harmless. You have to prove that it was harmful. That is a heavy lift, particularly in procedural fairness cases where you may be arguing about what you would have said if given the chance — a hypothetical exercise that courts are naturally sceptical about.
The bar is "realistic possibility," not probability. You do not have to prove the decision would have been different — only that it could have been. That sounds like a low bar. In practice, it is higher than it appears. Courts will look at the totality of the evidence and the strength of the case against you. If the case against you was strong on other grounds, showing that one additional factor could have tipped the scales becomes very difficult.
Some errors are still automatically jurisdictional. If the decision-maker was biased or if the decision was legally unreasonable, materiality does not apply. Those errors are inherently jurisdictional.
This is why expert legal advice matters so much at this stage. The materiality threshold has transformed judicial review from a process where identifying an error was largely sufficient to one where you must also prove the error's practical significance. That requires careful forensic analysis of the decision, the evidence before the decision-maker, and the realistic possibilities. It is not something you can do by reading the refusal letter at your kitchen table.
Coming Up Next
In Part 4, we look at what happens when the materiality threshold meets real cases run by experienced lawyers and barristers — people who knew the law, identified genuine errors, and still lost. These are not simple cases. They are sophisticated, well-argued challenges that were defeated by the question: but did it matter?
That is where the materiality threshold really shows its teeth.
In this series:
Part 2: The 2018 Case That Changed Everything: How the High Court Raised the Bar for Judicial Review
Part 3 (you are here): It's Not Enough to Prove They Got It Wrong: How the Materiality Threshold Expanded Beyond Errors of Law
Part 4: Why Even Strong Cases Fail: The Materiality Threshold in Practice
Related:
How Can Agape Henry Crux Help
If any of the following situations apply to you, we can advise you on whether judicial review may be an option:
Your visa was refused, and the refusal letter says it is not merit reviewable
Your visa was cancelled, and the cancellation notice says it is not merit reviewable
You missed the deadline to lodge with the ART
The Minister made the decision personally (s 501, s 501A, s 501BA)
The Department or Tribunal made a clear legal error, and you want it corrected without waiting years for merits review
You went through the Tribunal and lost, and you believe the Tribunal made a legal error
At Agape Henry Crux, our Accredited Specialists in Immigration Law regularly handle judicial review cases. You can schedule an appointment with one of our lawyers, Jason Ling or Angela De Silva, to seek professional advice by calling 02-8310 5230 or emailing us at info@ahclawyers.com.
We speak fluent English and Mandarin. We can also help you arrange an interpreter if this isn't your language.
Our founder and principal lawyer, Jason Ling, has been recognised in the 2026 edition of The Best Lawyers in Australia™. Agape Henry Crux is named as Best Immigration Law Firm 2025 - Sydney by APAC Insider Awards.
This article/presentation (“publication”) does not deal extensively with important topics or changes in law and is not intended to be relied upon as a substitute for legal or other advice that may be relevant to the reader's specific circumstances. If you find this publication of interest and would like to know more or wish to obtain legal advice relevant to your circumstances, please contact our office.
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