Expert witness immunity re-examined in Hastwell v Parmegiani


In Australia, expert witnesses have immunity from suit when they are instructed to prepare an expert report for use in litigation. That immunity also applies in relation to any evidence given in proceedings.

The general principle for witness immunity is founded on the rationale that witnesses should be able to give evidence freely in the interests of justice, without the possibility of threats of suit from unsatisfied litigants. Witness immunity also seeks to avoid multiple legal actions examining the same evidence.1

As the immunity has been abolished in the UK2, from time to time Australian Courts are called on to consider when immunity should apply.

Cavanagh J’s recent decision in Hastwell v Parmegiani3 provides a useful refresher of the issues a Court will consider when making that assessment.


The plaintiff had previously pursued an employment claim against his former employer, seeking damages for alleged victimisation and discrimination.

As part of that claim, the plaintiff’s former solicitors had lodged a complaint with the Australian Human Rights Commission (AHRC) seeking their assistance in resolving the matter; and retained a psychiatrist to examine the plaintiff and provide a report on issues relevant to the claim, including the nature and extent of any psychological conditions from which the Plaintiff was suffering and the cause of these conditions.

A letter of instruction addressed to the psychiatrist advised that ‘should this matter proceed to hearing, you may be called […] as an expert witness and be required to give oral evidence in court’. Also included in the instruction letter was a copy of the Federal Court Rules 2011 (Cth) and Federal Court Practice Note relevant to expert witnesses. The psychiatrist was also advised that they were required to specify that their expert report complied with the Practice Notice.

The report was prepared by the psychiatrist and contained an acknowledgement in accordance with the Federal Court Expert Witness Code of Conduct (Code). However, the report was never filed or served before the plaintiff’s former solicitors ceased to act for him. The plaintiff alleged that the expert opinion provided in the report was the reason that his former solicitors ceased to act for him prior to any conciliation of the claim with the AHRC.

The plaintiff subsequently commenced proceedings in the Federal Court against his former employer on similar grounds of alleged victimisation and discrimination. The expert report was not served in those proceedings before they were permanently stayed.

The plaintiff subsequently sued the psychiatrist for negligence, breach of fiduciary duty and breach of consumer guarantees as set out in the Australia Consumer Law (ACL). Damages were sought on the grounds that the psychiatrist’s conduct had caused the plaintiff significant psychiatric injury and subsequent significant losses of income, professional reputation, and out-of-pocket expenses. The plaintiff alleged that the report was false, misleading, incorrect, vague, and not fit for purpose and caused his former solicitors to cease to act for him and abandon his claim against his former employer.


Relying on the principles of witness immunity, the psychiatrist filed an application that the proceedings be dismissed on grounds that, by reason of expert immunity, they demonstrated no reasonable cause of action and had no prospects of success. He submitted that he had ‘absolute immunity’ as an expert witness who was instructed to prepare a medicolegal report for use in litigation.

The plaintiff argued that witness immunity required (a) a report; and (b) the giving of evidence, and submitted that the immunity did not apply in this case because:

a. The psychiatrist’s report was produced prior to litigation in the process of making a complaint to the AHRC;

b. The expert report was never served or used in the proceeding, meaning that the requirement for ‘the giving of evidence’ and that there be a connection between the report and any litigation was not met; and

c. The report was prepared for the dominant purpose of seeking advice from the psychiatrist as to whether the plaintiff could pursue a potential claim, not for any actual or contemplated court proceedings.

The plaintiff also submitted that comments by the High Court in Attwells v Jackson Lalic Lawyers Pty Ltd4 (‘Attwells’) that for ‘out-of-court-work’ to attract the immunity requires the advice to affect the conduct of the case in court and the resolution of the case by that court, limited the scope of the immunity such that it left open the type of action being pursued by the plaintiff.


After briefly considering the relevant legal authorities, including the well-established rule that the immunity applies to evidence given by witnesses in court, Cavanagh J confirmed that witness immunity from suit can extend to the witness’s out-of-court work.

In reaching his decision, his Honour confirmed that:

a. The witness immunity rule provides protection to experts retained to give evidence from all types of suits, including the causes of action in negligence, breach of fiduciary duty and under the ACL;

b. Attwells demonstrates that the application of the witness immunity rule is not contingent on whether a plaintiff actually decides to use the expert report in proceedings; and

It is necessary to consider the purposes for which the report is obtained, with his Honour indicating that if the psychiatrist was retained to advise the plaintiff about a potential claim, then there would at least be an argument as to the availability of the immunity meaning that the proceedings should not be dismissed at an early stage. However, the facts in this case did not support that argument.

Having noted those matters, Cavanagh J considered that:

a. The letter of instruction and expert report demonstrated that the plaintiff retained the psychiatrist to offer his opinions and prepare a report in accordance with the Code. The final report satisfied the requirements that it was of a kind typically commissioned by parties seeking compensation;

b. That the AHRC is not a court was not determinative. If the AHRC was unable to resolve the complaint, as was the case, the plaintiff would have to commence litigation. Witness immunity is not dependent on whether the expert ultimately gives evidence in proceedings;

c. There is a clear distinction between an expert giving advice to a person about prospects of success, evidence or issues in the proceeding, and an expert being retained in accordance with the Code;

d. The report was of a type which is regularly commissioned by those seeking compensation or other orders. Where the psychiatrist was asked to confirm compliance with the Code, said that he complied with it and had been told that he may be required to give evidence in court, his Honour did not accept that the psychiatrist was retained to advise on the prospects of the plaintiff making a claim; and

e. The fact that the report was commissioned prior to the lodgement of AHRC claim was irrelevant in circumstances where the plaintiff’s original claim made through his lawyers included a claim for compensation which, if not resolved, would require proceedings to be instituted.

His Honour therefore concluded that:

“there is nothing in Attwells which suggests that the immunity is not available to an expert preparing a medicolegal report in accordance with the Expert Witness Code of Conduct, irrespective of whether the report was obtained prior to the commencement of proceedings, or after the commencement of proceedings. Further, the immunity from suit is not dependent upon whether the author of the report actually gives evidence, or even whether there was any litigation…”


Accordingly, the decision confirms that an expert witness retained to provide a report in compliance with the Codes of Conduct whether before or after proceedings are commenced, and on the basis that evidence might be used in court, will be protected from suit by the principles of expert immunity.

1 D’Orta-Ekenaike v Victoria Legal Aid (2005) 223 CLR 1.
2 Jones v Kaney [2011] 2 AC 398.
3 [2023] NSWSC 1016.
4 (2016) 259 CLR 1.

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.

Michael Bath

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