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Defence Hub › Peer professional opinion defence
If a professional or their insurer has told you that the peer professional opinion defence means your claim cannot succeed, you may have been left feeling like the door has closed before it even opened. That reaction is understandable — but it is not necessarily correct.
This defence is real, it is codified in legislation across most Australian states and territories, and it does succeed in some cases. But Australian courts do not simply hand it to defendants on demand. They examine it carefully, apply an independent standard of reasonableness, and in many situations — particularly around warnings, causation, and irrational professional practices — they reject it.
DEFINITION
What is the peer professional opinion defence?
The peer professional opinion defence allows a professional who is sued for negligence to argue that their conduct was consistent with what other competent professionals in their field would have done in the same circumstances. If the court accepts that the professional acted in a manner widely accepted by peer opinion — and that opinion is not irrational — the claim may be defeated, even if the outcome for the claimant was harmful.
The peer professional opinion defence has its roots in the English case of Bolam v Friern Hospital Management Committee [1957] 1 WLR 582 — commonly known as the Bolam test. Under that test, a professional was not negligent if they acted in accordance with a practice accepted as proper by a responsible body of professionals in their field.
Australian courts accepted a version of this approach for decades. Then came Rogers v Whitaker (1992) 175 CLR 479. The High Court of Australia made a deliberate decision to move away from full Bolam deference, holding that the standard of care is ultimately a question for the court — not for the profession itself to determine. Professionals cannot simply point to what their peers do and expect that to end the inquiry.
That decision fundamentally changed the landscape. It signalled that Australian claimants would receive a more robust form of protection than their English counterparts, and it remains the foundational authority in this area today.
Following law reform reviews in the early 2000s, most Australian jurisdictions codified a modified version of the peer professional opinion defence in their Civil Liability Acts — preserving the concept but keeping it subject to judicial oversight.
The defence is now statutory in most jurisdictions. The governing provisions are:
| Jurisdiction | Provision |
|---|---|
| NSW | Civil Liability Act 2002 (NSW) s 5O |
| QLD | Civil Liability Act 2003 (QLD) s 22 |
| WA | Civil Liability Act 2002 (WA) s 5PB |
| TAS | Civil Liability Act 2002 (TAS) s 22 |
| SA | Civil Liability Act 1936 (SA) s 41 |
| VIC | Wrongs Act 1958 (VIC) s 59 |
| ACT | Civil Law (Wrongs) Act 2002 (ACT) s 43 |
| NT | No equivalent statutory provision — common law applies |
For the defence to operate, the defendant generally needs to establish three things:
1. Widely accepted practice
They acted in a manner widely accepted by peer professional opinion as competent professional practice.
2. Genuine peers
The opinion must be held by peers in the same or a similar professional field — not by generalists offering views on specialist conduct.
3. Not irrational
The opinion cannot be irrational. Courts retain the power to reject peer evidence that cannot withstand logical scrutiny, regardless of how widely it is held.
The burden of establishing all three elements rests with the defendant. Courts do not simply take expert evidence at face value — they examine what genuinely constitutes “widely accepted” practice, and they apply that test critically.
This is the section that matters most for anyone who has been told the defence stands in the way of their claim. There are four situations where it either does not apply at all, or where it cannot rescue an otherwise failing case.
Failure to warn about material risks
The most important limitation. Across the jurisdictions that have enacted this defence, the duty to warn a patient or client about material risks is explicitly excluded from its protection. A professional cannot rely on what their peers do — or don’t do — to defeat a claim that they failed to warn of a risk that a reasonable person in the claimant’s position would have wanted to know. This goes back directly to Rogers v Whitaker (1992) 175 CLR 479 and was confirmed in Rosenberg v Percival (2001) 205 CLR 434. In practice this carve-out is significant — a substantial number of medical and legal negligence claims involve an alleged failure to advise, and the peer professional opinion defence simply cannot be used to defeat them.
The irrationality threshold
Even where the defence technically applies, courts retain the power to reject a peer opinion that is irrational. In Dobler v Halverson [2007] NSWCA 335, the NSW Court of Appeal applied section 5O and examined whether the peer opinion advanced was genuinely widely accepted and capable of withstanding logical scrutiny. The case illustrates that courts are not passive recipients of expert evidence — they examine it critically. An opinion that cannot be rationally justified, even if endorsed by a number of practitioners, will not satisfy the test.
Causation is a separate question
The peer professional opinion defence goes to breach of duty — whether the professional’s conduct fell below the required standard. It has nothing to say about causation. Even if a professional successfully establishes that their conduct was consistent with peer opinion, the claimant may still succeed on causation grounds. Naxakis v Western General Hospital (1999) 197 CLR 269 and Tabet v Gett (2010) 240 CLR 537 both illustrate the way causation operates as a distinct and independent element.
Professions where courts apply closer scrutiny
Courts do not apply identical levels of deference across all professions. Legal professionals face a situation where courts are quite willing to form their own views about what competent legal practice looks like. Financial advisers operate within a detailed regulatory framework administered by ASIC, and their conduct is assessed against those regulatory standards as well as peer norms. An adviser cannot rely on peer opinion to justify conduct that falls below the regulatory floor.
The High Court’s decision in Vairy v Wyong Shire Council (2005) 223 CLR 422 reinforced the principle that courts apply an independent standard of reasonableness. They are not bound by what a profession considers acceptable. Expert evidence from peers is taken seriously, but it is weighed against the court’s own assessment of what a reasonable professional would have done.
When a defendant seeks to rely on peer professional opinion, courts examine:
That last point is one that experienced legal teams press hard. Courts are alert to the difference between genuine professional consensus and expert evidence procured for litigation purposes.
The defence operates differently depending on the profession involved. Here is how it commonly arises across the four professions most frequently subject to professional negligence claims.
The defence is invoked most frequently in medical negligence claims — covering diagnostic decisions, treatment choices, surgical approaches, and medication management. The warning carve-out is especially relevant here, since a significant proportion of medical claims involve an alleged failure to advise a patient of risks before a procedure. AHPRA is the relevant registration authority.
Accepted professional standards, Australian Standards, and building codes provide an external framework against which peer opinion is measured. Whether a professional's approach was consistent with those standards is often central to the analysis, giving courts a clear independent benchmark.
Courts apply careful scrutiny in legal negligence claims. Judges are well-placed to assess whether a particular piece of legal advice fell below the expected standard, and peer opinion does not carry the same weight it might in highly technical specialist fields. The Law Society and Legal Services Commissioner are the relevant oversight bodies.
Peer professional practice in financial advice is assessed alongside ASIC's regulatory requirements and the obligations under the Corporations Act 2001 (Cth). An adviser cannot rely on peer opinion to justify conduct that falls below the regulatory floor set by licensing obligations and the best interests duty.
Being told the peer professional opinion defence applies to your situation is not the end of the analysis — it is the beginning of a more detailed one. The relevant questions are whether the defence has actually been properly established, whether it covers the specific conduct in dispute, whether the warning carve-out applies, and whether causation remains live regardless of the breach analysis.
These are not questions that can be answered in the abstract. They turn on the facts of your particular situation, the professional involved, the jurisdiction, and the conduct that led to your loss.
If you have been advised that this defence stands in the way of your claim, it is worth getting an independent assessment before accepting that result. You can request a free case evaluation → to have your situation reviewed by a specialist, or use our Claim Eligibility Checker → to take an initial look at the elements of your situation.
The peer professional opinion defence rarely operates in isolation. In many claims, defendants raise several defences at once. Two that commonly appear alongside it are:
A professional may argue that the claimant’s own conduct contributed to the loss, even while relying on peer opinion to defend the standard of their practice. The two arguments run independently and can both reduce or defeat a claim if accepted.
Voluntary assumption of risk →
This defence has limited application in professional negligence claims, but it is occasionally raised where a claimant was expressly warned of a risk and proceeded anyway. Understanding where one defence ends and another begins is important when more than one is in play.
Both defences sit within the broader framework of how duty of care and breach are established. The breach of duty analysis must be resolved before any defence is even considered — understanding that threshold helps make sense of where the peer opinion defence fits.
It is a statutory defence available to professionals sued for negligence. If a professional can show that their conduct was widely accepted by peer professional opinion as competent practice, and that the opinion is not irrational, they may avoid a finding of negligence. The defence is codified in most state and territory Civil Liability Acts, but it is subject to important limitations — including an exclusion for failures to warn of material risks.
No. The duty to warn a patient or client about material risks is explicitly excluded from the peer professional opinion defence in the jurisdictions that have enacted it. A professional cannot point to what other practitioners do or don’t tell their clients to defeat a failure-to-warn claim. This exclusion comes from the High Court’s decision in Rogers v Whitaker (1992) 175 CLR 479 and has been confirmed in subsequent cases including Rosenberg v Percival (2001) 205 CLR 434.
Under the original English Bolam test, a professional was not negligent if they acted in accordance with a practice accepted by a responsible body of peers — regardless of whether the court thought that practice was reasonable. Australian courts departed from this in Rogers v Whitaker (1992), holding that the standard of care is ultimately a question for the court, not the profession. The statutory defences across Australian jurisdictions preserve the peer opinion concept but retain judicial oversight, including the ability to reject opinions that are irrational.
It may be raised, but financial advice is heavily regulated. A professional’s conduct is assessed against ASIC’s requirements and the obligations under the Corporations Act 2001 (Cth) as well as peer professional norms. An adviser cannot rely on peer opinion to justify conduct that falls below the regulatory floor. Courts apply careful scrutiny in this area, and the defence is more limited in its practical effect than in purely clinical professions.
Get independent legal advice before accepting that the defence succeeds. Whether the defence has been properly established, whether the warning exclusion applies, and whether causation remains open are all questions that require careful legal analysis specific to your situation. A free case evaluation is available — speak to a specialist before drawing any conclusions about the strength of your claim.
Our goal is to help people in the best way possible. this is a basic principle in every case and cause for success. contact us today for a free consultation.
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