More than 100 riot police surrounded the courthouse in Kuala Lumpur as Mr Anwar entered the building, but there were no sign of protestors.

Mr Anwar faces charges relating to corruption and sexual offences, but he denies the allegations and says he is the victim of a political conspiracy.

His sacking by the prime minister, Mahathir Mohammad, two months ago, prompted a wave of anti-government demonstrations.

US concerns

Meanwhile, the United States has again expressed concern about the trial.

The US State Department is calling for more international observers to be allowed into court.

On the first day of the trial on Monday, the presiding judges refused to allow observer status to some foreign diplomats and civil rights representatives, including a US embassy representative.

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

State Department spokesman James Rubin said: "We believe that given the enormous interest in this trial, it is in Malaysia's interest to follow the policy announced by the high court and allow spectators to observe the trial."

The White House said President Clinton would not have separate talks with the Prime Minister of Malaysia, Mahathir Mohammed, at an economic summit in the Malaysian capital, Kuala Lumpur, next week.

Anwar upbeat

Anwar says he was beaten shortly after his arrest

Appearing in court on Monday, Mr Anwar appeared in good spirits and told reporters he was "in good health and expecting a good trial".

Mr Anwar has pleaded not guilty to the initial four charges of corruption, related to his alleged illicit homosexual relationships.

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

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.