Chief Justice Andrew Cheung on Tuesday said the plagiarising acts of a High Court judge are not acceptable, and the Court of Appeal has ordered a retrial of the case involved.

Judge Wilson Chan is accused of handing down a judgement in which he copied 98 percent of the plaintiff's written submission on a trademark case in 2021.

Chan ruled that Singapore Medicine Company Ltd infringed the trademark of Wong To Yick Wood Lock Ointment Ltd, prompting the former company to seek an appeal.

In a written judgement issued last week, the Court of Appeal ruled that Chan's actions were considered as "judicial copying", and ordered a retrial under another judge.

Responding to media enquiries, the Judiciary said such acts were unfair to both parties and also affected public confidence in the courts.

Chief Justice Andrew Cheung said Chan, who is also a national security judge, had received a serious reprimand over his actions.