Raja Aziz Addruse, lead counsel for the sacked deputy premier, said Judge Augustine Paul let prosecutors introduce "highly prejudicial" evidence of alleged sexual misconduct -- including a semen-stained mattress -- and then ruled that it was irrelevant.

In the case which ended last April Paul let prosecutors amend the charges at the end of their case. This meant that the truth or falsity of the sexual allegations need not be proved -- only that Anwar had tried to cover them up.

Anwar, once heir apparent to Prime Minister Mahathir Mohamad, was convicted of four counts of corruption -- abusing his official powers to cover up allegations of homosexual and heterosexual misconduct.

Appeal court president Lamin Yunus and judges Ahmad Fairuz and Mokhtar Sidin are hearing his appeal against conviction and sentence.Raja Aziz told the court as the appeal began Monday that Paul had "given no credible reasons for allowing the amendments."

He said prosecutors had adduced "highly prejudicial" evidence -- such as the "famous mattress" with semen stains -- to try and prove the sexual allegations.

"We had gone on the basis of the original charges which smears the character of the appellant and now they amended it, saying it is not really that important," Raja Aziz added.

As grounds for appeal he also cited Paul's "drastic" measure to expunge all evidence related to the sexual allegations following the amended charges."This ruling was arbitrary," he said. "The expunging of evidence has deprived the defence of evidence favourable to it.

Anwar, starting another round in a 17-month legal battle which followed his sacking by Mahathir in September 1998, hugged his daughter Nurul Izzah and relatives as he arrived in court.

About one kilometer away, 28 people arrested after a pro-Anwar protest at the national mosque last September appeared in magistrates' court to face charges of illegal assembly. Their trial resumes Tuesday.

Several supporters staged a silent protest outside the magistrates' court and later the appeal court, with tape over their mouths and the slogan "Reformasi" (Reform) written on it.

They said they were highlighting curbs on freedom of speech.A police water cannon truck was parked in the city centre but no incidents were reported.

Raja Aziz also said Anwar had been charged under a law which was in the process of being repealed at the time.

He said Anwar, 52, had been charged under the 1971 Emergency Ordinance Number 22. But parliament's lower house had passed a resolution in October 1998 to annul the law effective from January that year.

Anwar's corruption trial began in November 1998.

Raja Aziz said parliament's upper house had not yet formally annulled the law. But despite this, "it would be invidious and oppressive to continue to subject the appellant to prosecution on the four charges."

He quoted a series of legal precedents to support his case.

"The prosecution amounted to an abuse of process because the offences under the charge originally framed would not have been in existence upon annulment of the ordinance," Raja Aziz said.

The US State Department, in a report released Friday, strongly criticised the conduct of the corruption trial.

Anwar was detained 18 days after his sacking, initially under an act allowing detention without trial, after leading mass anti-government protests.

He is separately on trial for sodomy, a crime punishable by up to 20 years, but says he is the victim of a high-level political conspiracy. The government says the courts are independent.The appeal hearing continues Tuesday.