Changing expert witnesses during proceedings

On 7 August 2025, Justice Beasley, in a class 1 matter, granted the Applicant’s notice of motion to vary prior orders for expert evidence made by the Court’s Registrar, by setting aside the Registrar’s orders with respect to changing two of the Respondent Council’s witnesses.

The Respondent Council had two expert witnesses who did not support all of the reasons for refusal of the DA the subject of the substantive appeal.

The Registrar had granted leave to the Respondent to change these two expert witnesses, to two alternative expert witnesses, who appeared to support all of the reasons for refusal.  The Applicant submitted that in seeking such orders, the Respondent was effectively ‘expert shopping’.  The Registrar had indicated that that point could be addressed in any cross examination at the hearing, before making the orders.

Parties’ expert witnesses are bound by Part 31 Division 2 of the Uniform Civil Procedure Rules 2005 (UCPR).  Rule 31.23 requires expert witnesses to comply with the Expert Code of Conduct set out at Schedule 7. Schedule 7 mandates that expert witnesses’ overriding duty is to the Court (and not to their respective clients).

The question for Beasley J was whether the Applicant had made out a case for relief from a Registrar’s decision.  The Applicant argued that in making those orders the Registrar erred ‘in holding that the question of expert shopping could be dealt with by cross examination’, that she failed to take into account the principle of expert evidence and that she did not consider the interests of justice.

The Respondent argued that nothing in the Registrar's decision, which concerned an issue of practice and procedure, amounted to an error of law.

In setting aside the Registrar’s orders, Beasley J ultimately held that the fact that the Respondent’s experts could not support all of the reasons for refusal was not a good reason for the Registrar to grant leave to the Respondent to change experts.

There was a complication in the matter that the Statement of Facts and Contentions was filed by the Respondent before the Local Planning Panel’s reasons were given and so the experts had to consider new matters.

Key takeaway

A full understanding of the Respondent’s issues needs to be gained by experts before they are identified in orders. Any party seeking to change an expert (or experts) at any juncture in the proceedings, must be aware that it may be difficult to do so if the sole reason arises from an expert’s change of view on some of the contentions in the case.

Please call one of our team members for further information or discussion.

Note: Potter v Woollahra Municipal Council [2025] NSWLEC 80 - case outcome published with the consent of the Council.