Sukma Dermawan, an Indonesian-born interior designer, was jailed for six months after admitting homosexual acts with Mr Anwar.

Mr Sukma's lawyers had filed a special application for habeas corpus arguing his conviction and jail term were unlawful.

They argue the court which sentenced him in September had no jurisdiction over his case, because he is a Muslim and should therefore be dealt with by the Islamic Sharia court system.

But the Malaysian High Court rejected their plea on Saturday, saying the lower Sessions Court did have the jurisdiction to decide on the sodomy case against Mr Sukma.

Mr Sukma's lawyer told reporters that he would appeal.

Another similar plea, made by Mr Anwar's former speech-writer, Munawar Ahmad Anees, had already been rejected by the high court.

'Duress' claim

Mr Munawar was jailed together with Mr Sukma, after both pleaded guilty to engaging in illegal sexual acts with Mr Anwar, but Mr Munawar later claimed that his confession was made under duress.

Mr Anwar was arrested shortly after the two men's conviction but has denied charges of sexual misconduct and corruption against him, saying they were politically motivated.

On Friday, the head of Malaysia's police intelligence read out in court his own report in which concluded that allegations of sodomy and adultery against Mr Anwar were unfounded.