Dupont & Chief Commissioner of Police and Anor

The appeal involved the respondents, the Chief Commissioner of Police and another, against an order for the production of documents under a subpoena, on the grounds of public interest immunity. The Family Court of Australia was tasked with determining whether the claim should be assessed under the common law or the Evidence Act 1995 (Cth). The court was also required to decide if the primary judge correctly applied the common law in assessing the documents for public interest immunity and whether the appeal was free from error in the context of the balancing exercise conducted.

The court considered whether the Evidence Act 1995 (Cth) applied to the subpoena, and if not, whether the common law was the appropriate framework for assessing the documents. It was found that while section 130 of the Evidence Act applied to the "admission into evidence" of a document, section 131A extended its scope in limited circumstances, including pre-trial proceedings such as subpoenas in Victoria. However, section 79 of the Judiciary Act 1903 (Cth) did not extend the application of section 131A of the Victorian Evidence Act, indicating that the intention was to handle public interest immunity in pre-trial procedures according to the common law.

The court examined the primary judge's application of the common law and their characterisation of the documents as "matters of state." It was determined that there was no discernible difference between the common law and the Evidence Act in terms of the test applied to determine whether a document would attract public interest immunity, and the terms could be used interchangeably. The primary judge had read the documents and appropriately balanced the competing aspects of the public interest, leading to the conclusion that there was no error in the primary judge's assessment.

The appeal was dismissed, and the costs order was made for the first respondent only, as the appellant had not established any appealable error and it was not necessary for the second respondent to participate in the appeal.