When to Engage an International Expert Witnesses

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Legal practitioners are faced with various options when determining which expert witness to engage in a particular trial. As discussed in our previous blog post, the use of first time expert witnesses versus experienced expert witnesses is one such decision. Another issue faced by legal counsel is whether to engage a local or an international expert. The ideal decision in a particular case is heavily influenced by the context of the trial and the issues which arise in the trial. Below we consider the issues surrounding the use of domestic and international experts and explore select New Zealand and US case studies relating to the use of international expert witnesses.

Domestic Expert Witnesses

Australian expert witnesses who have been domestically trained and specialise in national issues in their particular field are extremely useful in Australia-based litigation. In cases involving consideration of domestic codes of conduct or regulations (for example, construction disputes dealing with construction codes), a domestic, and at times state-based, expert witness is ideal for their familiarity with the domestic or state-based codes and regulations surrounding the industry.

Cases involving scientific issues unique to Australia such as Australian topography, geology or climate are also better suited to a domestic expert with practical experience with the Australian landscape. This may be relevant in cases such as bushfire class actions and Land and Environment Court hearings.

Furthermore, in patent cases it is critical that the expert has a sufficient connection to the jurisdiction in which they are providing evidence. A 2013 case study by Freehills Patent Attorneys[1] delved into the issue of utilising an international expert witness in a New Zealand-based patent case. The study drew attention to a New Zealand decision where an expert from Sweden was engaged to provide expert testimony. While the evidence of this expert was not disregarded, it was noted that the expert lacked a connection with the field in New Zealand and this factor may lower the weight of the expert’s evidence.

On top of this, an experienced domestic expert will also have greater knowledge of Australian court room procedures and requirements if they have previously served as an expert witness. Experts from civil jurisdictions are unlikely to be familiar with the procedures of a common law court room and will require additional guidance from legal counsel.

International Expert Witnesses

There are numerous reasons why counsel may choose to utilise an international expert. In multi-jurisdictional cases, lead counsel may seek to utilise the same expert across different jurisdictions for consistency, cost savings, and to avoid briefing multiple witnesses on the same issue.

Additionally, the expert evidence required may be in such a niche industry that the options available to counsel are extremely limited and an international expert may be the only expert available with the requisite experience. For issues which are not nation-specific, for example certain medical or aviation expert evidence, this problem should not arise, although the use of an international expert witness may be more costly for the client. On the other hand, if the international expert is testifying about an Australian specific issue consideration should be given to the weight of such an expert’s evidence.

Another key area where international expert witnesses are often utilised is in cases involving foreign law elements. As in the case study below, in such cases judges must rely on experts in order to understand the laws of countries in which they are not formally trained. Set out below is a case study involving elements of foreign law and concerning the use of foreign experts in US securities cases.

Case study – the use of international experts in complex international securities cases filed in the US

Due to the increasingly global nature of financial markets, US courts have seen a rapid expansion of cross-jurisdictional cases in the past two decades. Judges in the US had traditionally rejected the application of foreign law due to the reliance on expert witness testimony that came with its application. The 2012 case of Stichting Pensioenfonds ABP v. Credit Suisse Group AG[2]  provides a key example of how US courts are adapting to the use of foreign experts to enable foreign law (in this case Dutch law) to be applied in relevant cases.

In this case the issue in question was whether or not certain claims were time barred under Dutch law. Under New York law, when a non-resident sues on a cause of action accruing outside of New York, the cause of action must be within time limits in both New York and the jurisdiction where the cause of action accrued (in this case the action accrued in the Netherlands). In this particular case, the judge took a more active role in the trial by independently reviewing the foreign statutes and considering the expert’s testimony before making a conclusion as to whether or not the expert testimony would be accepted. Beyond expert witness testimony the court also requested affidavits from foreign law experts to establish various facts and elements of Dutch law. Additionally, since foreign law experts were utilised by both parties the judge also considered oral arguments between the two experts on the issues at hand.


The decision to retain a domestic or international expert witness should be considered on a case by case basis after reflecting on the context and key issues at hand. While generally a domestic expert is preferred, the case study above demonstrates that there are unique situations where engaging an international expert is not only preferable but necessary.


[1] NZ Patent Oppositions – Can I Use a Foreign Expert? (Tracey Hendy, 04 March 2013)
[2] 2012 N.Y. Slip Op. 52433(U) (N.Y. Sup. Ct. 2012)

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