Jakarta – Indonesian authorities blocked attempts by two activists on Wednesday to call jailed East Timorese rebel leader Xanana Gusmao as a witness in their trials on charges of subversion.

The attorney-general's office also intervened to stop the South Jakarta State Court calling outspoken sacked legislator Sri Bintang Pamungkas as a witness in the trials of the two members of the unrecognised People's Democratic Party (PRD).

"They had already received the letters which called them to come as witnesses but today it was suddenly changed because those in power were playing games," one of the defendants Wilson Bin Nurtias told reporters before his trial.

"Today (they) cannot come, not because (they) do not want to come," Wilson said from his holding cell flanked by his colleague I Gusti Agung Anom Astika who was being tried in a separate court.

Indonesians vote on Thursday in elections to the country's House of representatives after some of the worst political violence in three decades.

Supporters of the two defendants handed to journalists at the court a copy of a letter from the attorney-general's office dated Monday saying the Attorney-General's department opposed the presence of Gusmao and Bintang as witnesses.

"The calling of the witnesses Xanana Gusmao and Sri Bintang Pamungkas was irrelevant to the accusations put forward by the prosecutors," Dedi Pridasa from the South Jakarta office of the department said in the letter.

"The arguments of the accused had a connection with other cases involving (other PRD members) which have already been proved in previous trials," Pridasa said.

Last month, 12 PRD members were given jail terms of between 18 months and 13 years after trials in Jakarta and Surabaya when they were found guilty of subversion because their group did not take the state ideology as its founding priniciple.

Gusmao headed the guerrilla movement in the former Portuguese colony of East Timor, invaded and annexed by Indonesia a move not recognised by the United Nations, until his capture in 1992. He is serving a 20 year jail term. The PRD advocates a referendum for self determination in East Timor but Jakarta regards the territory as its 27th province.

Bintang, serving a 34-month term for insulting President Suharto, also faces fresh subversion charges for advocating an election boycott and end to Suharto's 30-year rule like the PRD.

Wilson walked out of the court after reading statements from Gusmao and Bintang which he said showed they had been blocked from attending.

Shouting that the court system was unfair, he left the courtroom telling journalists it was unlikely he would return for the remainder of the trial.

"I don't think so. I don't care about the court," he said.