Duong v The Queen; Sem v The Queen

These appeals concerned the admissibility of evidence obtained by police in circumstances where the police had not complied with the requirements of s 138 of the *Evidence Act 1995* (NSW). The applicants, Duong and Sem, were convicted of drug offences in the District Court of New South Wales. The Court of Criminal Appeal of New South Wales dismissed their appeals against conviction. The High Court of Australia granted special leave to appeal.

The central legal issue before the High Court was whether the evidence obtained by police, which was prima facie inadmissible due to breaches of s 138, should have been admitted under s 138(3) of the *Evidence Act 1995* (NSW). This required the court to consider the balancing exercise mandated by s 138(3), which involves weighing the desirability of admitting the evidence against the undesirability of admitting evidence obtained in contravention of the law.

The High Court, in a joint judgment, held that the Court of Criminal Appeal had erred in its application of s 138(3). The High Court emphasised that the discretion conferred by s 138(3) is not a broad one and requires a careful and principled assessment of the competing interests. It found that the Court of Criminal Appeal had not adequately considered the weight to be given to the contravention of the law, particularly in circumstances where the contravention was not minor or technical. The High Court reiterated that the purpose of s 138 is to deter unlawful conduct by police and that this purpose must be given significant weight in the balancing exercise.

The High Court allowed the appeals, quashed the convictions, and remitted the matters to the Court of Criminal Appeal to determine whether, in the absence of the improperly obtained evidence, there was sufficient evidence to support the convictions.