Chen v The Queen

Chen appeals against his conviction for various drug trafficking offences. The appeal focuses on the admissibility of expert evidence provided by a linguist and the propriety of jury directions given by the trial judge. The High Court was asked to determine the admissibility of expert opinion evidence under section 79 of the Evidence Act 1995 (NSW), the necessity of the expert possessing specialised knowledge, and whether the evidence should be excluded under sections 135 or 137 of the Evidence Act where its credibility, reliability, and accuracy are challenged. The court also considered whether the evidence should be inadmissible where the expert witness code of conduct, as set out in Part 75 r 3J of the Supreme Court Rules 1970 (NSW), was not complied with. Specifically, the court examined whether the evidence of an expert who was not aware of the expert witness code of conduct should be excluded under sections 135 or 137 of the Evidence Act. Additionally, the court evaluated whether the judge failed to provide the jury with necessary directions following the Crown's address, which allegedly suggested a reversed onus of proof.

The High Court determined that the expert opinion evidence was admissible under section 79 of the Evidence Act. The court found that the linguist's specialised knowledge was sufficient to qualify as expert evidence. The court held that the evidence should not be excluded under sections 135 or 137 of the Evidence Act because the challenge to its credibility, reliability, and accuracy did not warrant exclusion. Regarding the expert witness code of conduct, the court found that the expert's lack of awareness of the code did not render the evidence inadmissible. The court also found that the judge had adequately directed the jury, and there was no suggestion of a reversed onus of proof. The court concluded that the trial judge's directions to the jury were sufficient, and there was no miscarriage of justice. The court held that the expert evidence was properly admitted and the trial judge's directions were adequate.

The High Court dismissed the appeal, upholding Chen's conviction. The court found no error in the trial judge's handling of the expert evidence or the jury directions. The decision confirms the trial judge's discretion in determining the admissibility of expert evidence and the adequacy of jury directions in criminal trials. The court's reasoning reinforces the importance of specialised knowledge for expert witnesses and the need for expert witnesses to be aware of the expert witness code of conduct. The outcome of the appeal reinforces the trial judge's authority in managing expert evidence and jury instructions in criminal proceedings.