Case Study: Expert witnesses and legal professional privilege

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Roach v Page (No 17) [2003] NSWSC 973

This case considered whether documents which constituted communications or notes of communications between defence counsel and their expert witness were subject to legal professional privilege.


The plaintiff, in this case, challenged a claim of legal professional privilege made by the defendants in relation to certain documents produced in court under subpoena. These documents were described in a manner that indicated that they were communications or notes of communications between the defendant’s legal counsel and their expert witness.

The Relevant Law

At the time of the proceedings, the relevant provision of the Supreme Court Act 1970 (NSW) was Part 36, rules 13 and 13C(2) which provided as follows:

13 Privilege

(1)  This rule applies where:

(a)  the Court, by subpoena or otherwise, orders any person to produce any document to

(b)  …

(c)  …

the Court…and neither Part 3.10 of the Evidence Act nor Part 3.10 of the Evidence Act 1995 of the Commonwealth is applicable.

(2)  The Court shall not compel…production of a document…unless and until the Court directs that the production…shall not be prevented by this subrule:

(a)  over the objection of a person if evidence of the document…could not be adduced in the proceedings over the objection of the person, by virtue of the operation of Part 3.10 Division 1 of the Evidence Act…”


Unless the Court otherwise orders:

(a)  at or as soon as practicable after the engagement of an expert as a witness, whether to give oral evidence or to provide a report for use as evidence, the person engaging the expert shall provide the expert with a copy of the code,

(b)  unless an expert witness’s report contains an acknowledgement by the expert witness that he or she has read the code and agrees to be bound by it:

(i)  service of the report by the party who engaged the expert witness shall not be valid service for the purposes of the rules or of any order or practice note, and

(ii)  the report shall not be admitted into evidence,

(c)  oral evidence shall not be received from an expert witness unless:

(i)  he or she has acknowledged in writing, whether in a report relating to the proposed evidence or otherwise in relation to the proceedings, that he or she has read the code and agrees to be bound by it, and

(ii)  a copy of the acknowledgement has been served on all parties affected by the evidence.”

At the time of the decision, Part 3.10 Division 1 of the Evidence Act 1995 (Cth) provided as follows:

119 Litigation

Evidence is not to be adduced if, on objection by a client, the court finds that adducing the evidence would result in disclosure of:

(a)  a confidential communication between the client and another person, or between a lawyer acting for the client and another person, that was made, or

(b)  …

for the dominant purpose of the client being provided with professional legal services relating to an Australian…proceeding (including the proceeding before the court) …”

Also relevant to the determination was Schedule K of the Supreme Court Act 1970 (NSW) which provided, so far as is relevant:

Application of code

  1. This code of conduct applies to any expert engaged to:

(a)  provide a report as to his or her opinion for use as evidence in proceedings or proposed proceedings, or

(b)  give opinion evidence in proceedings or proposed proceedings.

General Duty to the Court

  1. An expert witness has an overriding duty to assist the Court impartially on matters relevant to the expert’s area of expertise.
  2. An expert witness’s paramount duty is to the Court and not to the person retaining the expert.
  3. An expert witness is not an advocate for a party.

Arguments made

The plaintiffs argued that in the context of Part 36, rule 13C and Schedule K, the dominant purpose of communications between defence counsel and the expert witness was not the provision of legal services to a client, but rather the provision of assistance to the court. This was because assistance to the court must be the witness’ dominant purpose in providing an opinion for use in the proceedings.


Sperling J held that the claim for the privilege was not negated by the description of the documents.

Sperling J held that despite the duties to the Court set out in Schedule K, the main purpose of communications between a party’s legal representatives and an expert witness is to assist the party as the predominant purpose of such communications is to bring forward expert evidence in aid of the party. Were it not for this purpose, the expert would not be engaged in the first place, and the witness’ duty of impartiality to the court does not displace that integral purpose of the expert witness.

Sperling J held that the key downfall in the plaintiff’s argument was their failure to appreciate the adversarial nature of the proceedings:

No party is under an obligation to adduce expert evidence to assist the court. No expert is obliged to provide evidence to assist the court. …. The court receives the benefit of assistance from an expert only if it suits a party to adduce such evidence…. The witness’s evidence must be impartial, but communications with a view to securing and facilitating the provision of such evidence are entered into for the purpose of assisting the party, not for the purpose of assisting the court.”

Sperling J additionally held that the common law position that communications with a potential witness are protected by legal professional privilege is clear and entrenched. Therefore, a clear expression of legislative intent is required before the common law can be taken to be abrogated in relation to expert witnesses. Sperling J found no such expression of intent in the legislative provisions discussed.

Broader issues

Sperling J also held that the broader implications of the arguments made by the plaintiff work to defeat their claims:

At common law, legal professional privilege attaches to communications with any prospective witness. A lay witness is bound, to tell the truth. The honest lay evidence is of no less assistance to the court than honest expert evidence. The plaintiffs’ argument would, therefore, apply equally to communications with a prospective lay witness. The argument accordingly runs against the common law principle in relation to witnesses generally, expert and lay alike. It is all or nothing. No intent to abolish the principle altogether can be found in the rules or in the Evidence Act.”


This case entrenches the legal principal that communications between expert witnesses and legal counsel, regardless of the additional duties imposed on expert witnesses, remain subject to legal professional privilege. This case serves as a safeguard for counsel seeking to rely on legal professional privilege to protect communications with their expert witnesses while presenting a clear roadblock for counsel seeking to compel the production of communications between counsel and their expert witnesses.

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