But the day ended amidst controversy over the presiding judge's refusal to allow observer status to foreign diplomats and civil rights representatives.

BBC Asia Correspondent Matt Frei: After this trial Malaysia will never be the same again

The judge, Augustine Paul, said allowing official observers would be an "insult to the court" and give the impression "it may not be dispensing justice."

"The presence of these people would amount to interference in the powers and functions conferred on me by the constitution," the judge told the packed Kuala Lumpur courtroom.

David Willis reports from Kuala Lumpur

The run up to the trial has provoked unrest and demands for political reform on a scale not seen in the country for many years. It has also attracted strong international interest.

Riot police and paramilitary troops were in position around the high court and although a crowd of Mr Anwar's supporters gathered nearby, there was no trouble.

Limited space

Anwar says he was beaten shortly after his arrest

The judge said whilst there would be no official observers, representatives of various monitoring groups were permitted to observe the trial from the public gallery.

But there are a limited number of seats in the gallery and several diplomats are reported to be considering lodging a complaint with the Malaysian authorities.

Mr Anwar has pleaded innocent to the initial four charges of corruption, related to his alleged illicit homosexual relationships.

Simon Ingram in Kuala Lumpur on the background to the trial

More than 20 members of his family were in also in court, including his eldest daughter, Nurul Izzah Anwar, who has rallied international support for her detained father.

Each charge carries a maximum penalty of 14 years in jail and a 20,000 ringgit ($5,000) fine.

Defence arguments

Anwar's daughter wore a badge in support of her father

In a day of legal and technical argument his defence team tried, unsuccessfully, to have the case thrown out altogether.

They also suggested that the judge hold Prime Minister Mahathir Mohamad in contempt following comments reported in Malaysian newspapers that a conviction would help preserve the ethnically diverse country's racial harmony.

Amnesty International lawyer Mark Daley: "There seems to be a use of these laws to stifle dissent"

The judge had earlier issued a ban on public discussion of the case.

Mr Anwar has said he is the victim of a high level political conspiracy and says he was beaten unconscious by police shortly after his arrest.

'Critical test'

He also faces another six of corruption and of sodomy, which is illegal in Malaysia.

BBC South East Asia Correspondent Simon Ingram: A difficult first day for the defence

Human Rights group Amnesty International has described the trial as a "critical test for human rights in Malaysia."

Until his dismissal in September, Mr Anwar was regarded as the natural successor to the prime minister.

An application for a 'watching brief' by the Malaysian Bar Association, which would have given the Association's lawyers the right to raise matters in court, was also rejected.

The case has provoked widespread anti-government protests

The BBC's correspondent in Kuala Lumpur, Simon Ingram, says many observers regard the case as a political show trial despite government assurances to the contrary.