WA Expert Witness Rules 2025: What Lawyers & Insurers Must Know
The 2025 Shift in Expert Witness Psychology: What Western Australia's New Rules Mean for Your Case
If you are a lawyer, insurer, or claims manager involved in litigation in Western Australia, the way you commission and manage psychological expert evidence has fundamentally changed. Reforms introduced in late 2024 and now in full effect across 2025 are demanding earlier precision, clearer instructions, and a stronger understanding of the ethical boundaries that govern expert psychological witnesses.
For those navigating medico-legal psychological reports, criminal injuries compensation reports in WA, or personal injuries psychological reports in Perth, these changes are not procedural footnotes — they are critical steps that can determine whether a report is admissible, persuasive, and compliant.
The Harmonised Expert Witness Code of Conduct: Now Formally Adopted in WA
On 7 November 2024, the District Court of Western Australia issued a revised Notice to Practitioners, formally adopting the Harmonised Expert Witness Code of Conduct. This replaced earlier versions of the notice and placed the Code's obligations squarely at the centre of civil litigation practice in WA.
The core principle of the Harmonised Code is straightforward but consequential: an expert witness's paramount duty is to the court, not to the party who engaged them. For psychological experts, this means:
- Opinions must be based on sound psychological methodology and evidence, not advocacy for a client's position
- Reports must disclose any limitations in the data, assessment, or available information
- Experts must acknowledge when a question falls outside their area of expertise
- Any changes in opinion must be communicated promptly to all parties
It is worth noting that the November 2024 notice also clarified an important nuance: medical experts in certain personal injury matters may have different compliance requirements under Rule 47B of the District Court Rules 1996 (WA). Lawyers managing personal injuries psychological reports in Perth should confirm with their psychologist which specific provisions apply to their matter and ensure instructions are framed accordingly.
The New Requirement for Early Precision: Questions Must Be Defined Sooner
Perhaps the most practically significant change for litigation teams is the shift in when expert questions must be formulated. Under WA's updated procedural rules, lawyers are now required to define specific questions and the underlying assumptions to be put to psychological experts at a much earlier stage in the litigation process.
Previously, it was common practice for questions to be finalised shortly before the expert completed their report — sometimes even after preliminary discussions with the expert. That approach is no longer acceptable. The new rules require that:
- Specific, clearly scoped questions are prepared before the expert is formally engaged
- Underlying factual assumptions are identified and documented in advance
- Instructions are provided in writing, forming part of the expert's disclosure to the court
For insurers managing workers' compensation claims or motor vehicle accident assessments, this means internal claims teams must engage legal counsel earlier to ensure the referral questions to psychological experts are legally sound and procedurally compliant before the assessment is booked.
Expert Conclaves vs. Expert Conferences: A Distinction Unique to WA
Western Australia maintains a procedural distinction that practitioners from interstate or overseas often overlook. In WA courts, an expert conclave and an expert conference are not interchangeable terms — they carry distinct meanings under the court rules.
- An expert conclave is a facilitated meeting between opposing experts, typically ordered by the court, aimed at identifying areas of agreement and disagreement before trial
- An expert conference has a different procedural purpose and is governed by separate rules
This distinction matters significantly in psychological injury matters, where opposing experts may hold differing views on diagnosis, causation, or prognosis. Ensuring your psychological expert understands WA's specific procedural framework — and has experience participating in expert conclaves — is an important factor in selecting the right practitioner.
The Family Court: A Preference for Single Expert Witnesses
In the Family Court of Western Australia, proceedings involving children increasingly favour the appointment of a Single Expert Witness rather than competing experts from each party. Where an Independent Children's Lawyer (ICL) is involved, this preference becomes even more pronounced.
This approach is consistent with the Family Law Act 1975 (Cth) and the court's obligation to prioritise the best interests of the child. For psychologists preparing reports in family law matters, it reinforces the importance of impartiality, structured clinical methodology, and transparent reasoning — all of which align directly with the obligations under the Harmonised Code of Conduct.
Why the Treating Psychologist Cannot Be the Expert Witness
One of the most important ethical principles governing psychological reports for court in 2025 is the strict prohibition on dual roles. AHPRA-registered psychologists are ethically bound to avoid acting simultaneously as a treating clinician and a medico-legal expert for the same individual.
This matters for two key reasons:
- Objectivity: A treating psychologist's primary obligation is to the therapeutic wellbeing of their client, which creates an inherent conflict with the court-focused objectivity required of an expert witness
- Credibility: Reports from practitioners who blur these roles are increasingly challenged during cross-examination and may be given reduced weight by the court
For individuals pursuing criminal injuries compensation reports in WA or personal injury claims, this means their treating psychologist and their medico-legal assessor should be — and ethically must be — different practitioners.
What This Means for Criminal Injuries Compensation Claims in WA
The Criminal Injuries Compensation Act 2003 (WA) requires claimants to demonstrate psychological harm arising from a criminal act. The standards applied to psychological reports in these matters are increasingly rigorous, and assessors are expected to:
- Apply structured clinical assessment frameworks
- Clearly distinguish between pre-existing conditions and harm caused by the relevant incident
- Address causation in terms that align with legal, not merely clinical, standards
- Comply with expert witness obligations even in tribunal and compensation settings
The 2025 procedural environment means that criminal injuries compensation reports in WA must be prepared by psychologists who understand both the clinical and the legal dimensions of their task.
Practical Steps for Lawyers and Insurers Commissioning Psychological Reports in 2025
To ensure your matter is not delayed or your report challenged on procedural grounds, consider the following steps:
- Engage your psychologist early — before questions are finalised, not after
- Prepare written instructions that include clearly articulated questions and factual assumptions
- Confirm AHPRA registration and medico-legal experience before making a referral
- Clarify the applicable rules — whether Rule 47B applies to your matter, and which court or tribunal will receive the report
- Avoid referring treating practitioners as expert witnesses for the same client
- Ask about conclave experience if the matter is likely to proceed to hearing in the District Court
Work With a Forensic Psychology Practice That Understands the 2025 Landscape
At Cygnet Medico-Legal Psychologists, we are an AHPRA-registered forensic psychology practice based in Western Australia, with deep experience preparing medico-legal psychological reports that meet the procedural and ethical standards now required in 2025.
Our services include:
- Medico-legal psychological reports for civil litigation
- Criminal injuries compensation reports under the Criminal Injuries Compensation Act 2003 (WA)
- Psychological reports for court, including pre-sentencing, fitness to stand trial, and expert witness reports
- Personal injuries psychological reports for Perth-based claims
- Workers' compensation and motor vehicle accident psychological assessments
We work directly with lawyers, insurers, and self-represented individuals, and we are experienced in meeting Western Australia's specific procedural requirements — including compliance with the Harmonised Expert Witness Code of Conduct and participation in expert conclaves.
To discuss a referral or to obtain a fee schedule, contact our offices:
- Fremantle: (08) 9467 6373
- Midland: (08) 9467 7676
Early engagement is now not just best practice — it is a procedural necessity. We are here to help you get it right from the outset.