The Peer Professional Opinion Defence

All State (but no Territory) jurisdictions in Australia contain a provision in their civil liability legislation whereby a professional can defend a claim alleging a breach of a duty of care by asserting that the impugned conduct was consistent with what is accepted in their field as competent professional practice.1

The defence is available to a claim for economic loss which is alleged to arise from a failure to exercise reasonable care and skill, whether the claim is for a breach of a common law duty of care or a statutory or contractually assumed duty of care that is concurrent and coextensive with the common law duty.

There are variations of the defence across the States. Broadly speaking the defence provides that a person who provides a professional service will not be liable for a breach of duty arising from the provision of that service if they can demonstrate they acted in a way (at the time the service was provided) that was widely accepted by peer professional opinion as competent professional practice.

In raising the defence, it is not necessary for the professional to demonstrate that the practice is ‘universally’ accepted for it to be considered ‘widely’ accepted.  It is also open for the court to rely on an opinion and find that the defence applies where there are differing peer professional opinions widely accepted by a significant number of respected practitioners in the field. 

The defence will not apply if the court finds the opinion is irrational or unreasonable, nor will it apply to liability arising from a failure to advise or warn the client. As to the irrationality exception, the New South Wales Court of Appeal found in South Western Sydney Local Health District v Gould that the exception should only rarely be available and that it is a:

‘…seriously pejorative and exceptional thing to find that a professional person has expressed an opinion that is “irrational”, and even more exceptional if the opinion be widely held…’.2

On that basis, the fact there might be mutually exclusive views or practices that are widely accepted by peer professional opinion as competent professional practice does not, of itself, mean there is no rational basis for the practice.

A ‘Defence’

While commonly characterised as a ‘defence’, the New South Wales Court of Appeal confirmed in Sparks v Hobson; Gray v Hobson3 the provisions do not operate as a ‘defence’ as such. That is because if the defendant successfully raises it, they will be found to have acted in conformity with the requisite standard of care. Proving the elements of negligence against the professional consequently becomes unnecessary.

Professional negligence claims can often involve a contest between the weight the court gives to the parties’ competing expert evidence about whether the professional’s conduct has met the required standard of care. The benefit to a defendant of raising the peer professional opinion defence is that if they can establish their conduct was in accordance with widely accepted professional practice, that contest may never ensue. Of course, the plaintiff’s evidence may be relied on by the court to find that the practice was not widely accepted, and the plaintiff will invite the court to determine the standard of care in accordance with that evidence.

Successfully Raising the ‘Defence’

Expert evidence

In practice, it is necessary to raise the defence during a trial with all other evidence to be weighed by the trial judge.  The defence can only be successfully raised by adducing expert evidence in support of it. 

In Wingecarribee Shire Council & Ors v Lehman Brothers Australia Ltd (ACN 066 797 760) (in Liq),4 where a financial services adviser in New South Wales asserted that their advice was consistent with peer professional practice, Justice Rares noted that ordinarily, professional practice is established by calling evidence from a professional who can speak to what competent members of the profession would do in a particular context or situation.5

Similarly, in Grinham v Tabro Meats Pty Ltd6, in describing the requirements of the peer professional opinion defence under the Victorian legislation, Forest J noted that the defence is directed to the manner in which the professional acted in the circumstances confronting them. The court must consider the opinion of other professionals as to the way in which the defendant carried out or failed to carry out the tasks being impugned in the proceeding.

The expert(s) should be suitably qualified in the specific area of conduct being impugned in the proceedings.  A bald statement from an expert, irrespective of their experience, that a professional has acted in acted in a manner that is “widely accepted” as being competent professional practice is unlikely to be enough.7

The expert should identify the particular conduct (i.e. how the professional, in fact, acted) and the peer opinion supporting that the specific conduct as ‘widely accepted’ practice.8

A standard of competent professional practice cannot be identified in the abstract.  It must relate specifically to the negligence alleged, by reference to the specific duties the professional has been engaged to perform. To the extent the expert provides evidence of an accepted practice at a high level of generality, it risks being found not to appropriately encapsulate the relevant conduct of the particular case.9

It is also necessary for the expert to be appropriately and accurately briefed to provide an opinion based on the specific circumstances confronting the professional at the time. The defence depends on the facts as found by the court.  If an opinion is based upon inaccurate assumptions or errors in the facts, it risks the court finding that the practice has not been established for the specific set of circumstances.

For example, Mules v Ferguson10 involved a claim against a doctor arising from the doctor’s failure to diagnose a disease that left the plaintiff blind, deaf and with other disabilities. At first instance, the court concluded that the defendant acted in a way widely accepted by a significant number of respected practitioners in the field as competent professional practice.11

In considering the application of the defence, the Queensland Court of Appeal said the defence needed to identify the particular conduct (i.e., how the professional, in fact, acted) and the peer opinion supporting that conduct as widely accepted practice.12

The Court of Appeal concluded that the evidence established that the defendant, in failing to conduct a physical examination of the plaintiff when she presented with those symptoms, did not act in a way widely accepted by a significant number of respected practitioners in the field as competent professional practice.13 The Court said the trial judge was in error in relying on expert opinion that was not based (as the trial judge had found) on the plaintiff’s specific symptoms. Therefore, there was no evidence satisfying the trial judge that the defendant had discharged her evidential onus.14

Pleading the defence

As the onus of proof to establish the defence rests with the defendant, it is also necessary to plead material facts to claim the defence.15  Simply reciting the words of the applicable section is insufficient, and “a sufficient articulation of the defendant’s manner of practice in the particular case, and an articulation of the competent professional practice being relied upon” is required.16

Among other things, it is likely incumbent on a defendant to specifically plead, and put in issue:

  1. The specific conduct that the defendant says is competent professional practice.
  2. The facts, matters and circumstances relied upon to assert that the given practice is widely accepted as being competent practice.
  3. The fact that the defendant adopted that practice in the given circumstances.


The peer professional opinion defence has been raised successfully by defendant professionals in several cases.  However, as outlined above, the defence is not all-encompassing.  Further, the evidential and pleading onus placed on the defendant to make out the defence is far from straightforward and risks putting the parties at extra expense.

In certain professional negligence cases, careful regard should be had at the outset as to whether the defence is maintainable, by way of a discussion with an appropriately qualified expert. Care must be taken to ensure the opinion sought properly addresses the specific circumstances of the case and the ambit of the defence.

1 CLA (Qld) s 22; CLA (NSW) s 5O(1); Wrongs Act (Vic) ss 57– 60; CLA (Tas) ss 21–22; CLA (SA) ss 40–41; CLA (WA) ss 5PA–5PB.
2 South Western Sydney Local Health District v Gould [2018] 97 NSWLR 513 [96].
3 [2018] 361 ALR 115.
4 [2012] 301 ALR 1.
5 Ibid, 290,
6 [2012] VSC 491, [181].
7 Sparks v Hobson; Gray v Hobson [2018) 361 ALR 115.
8 Mules v Ferguson [2015] QCA 5, [191].
9 Sparks v Hobson; Gray v Hobson [2018) 361 ALR 115.
10 [2015] QCA 5.
11 Mules v Ferguson [2014] QSC 51, [273]–[276].
12 Mules v Ferguson [2015] QCA 5, [191].
13 Mules v Ferguson [2015] QCA 5, [76]–[89].
14 Ibid [191]–[201].
15 Sydney South West Area Health Service v MD [2009] NSWCA 343; [2009) 260 ALR 702
16 Garling, Justice P — “Civil Liability Act 2002 – Burden for a Defendant – NSW Bar Association Personal Injury Conference” [2014] NSWJSchol 14.

This article may provide CPD/CLE/CIP points through your relevant industry organisation.

The material contained in this publication is in the nature of general comment only, and neither purports nor is intended to be advice on any particular matter. No reader should act on the basis of any matter contained in this publication without considering, and if necessary, taking appropriate professional advice upon their own particular circumstances.

Mark Brookes
Greg Stirling
Special Counsel
Katie Proctor

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