The Sri Lankan general who lost his bid for the presidency after leading the army to victory during the civil war appeared before a military court in Colombo on Tuesday.

Gen. Sareth Fonseka, who led government troops in their fight against the Tamil Tigers, was arrested last month, shortly after he made an unsuccessful bid to unseat President Mahinda Rajapaksa.

Military spokesman Maj.-Gen. Prasad Samarasinghe said Fonseka, accompanied by his lawyer, appeared before a three-member panel at the country's navy headquarters Tuesday to face charges that he prepared the groundwork for his presidential campaign while still in military uniform.

A second charge that Fonseka violated regulations in purchasing military hardware will be taken up Wednesday, he said.

Anura Dissanayaka, a lawmaker and Fonseka ally, said the former military chief objected to the court martial because he felt the panel was biased against him. Dissanayaka said that Fonseka said the panel included two men Fonseka had disciplined when he ran the army.

The panel's third member was a close relative of the current army commander who initiated the court-martial, he said.

Fonseka also argued that an army commander cannot face a court martial.

Many have been critical of the proceedings and expressed concerns that Rajapaksa is using all the levers of power to quash any opposition to his rule.

"Sarath Fonseka's arrest continues the Rajapaksa government's post-election crackdown on political opposition," said Sam Zarifi, Amnesty International's Asia-Pacific director.

Fonseka's wife Anoma said she opted not to attend the hearing because the charges against her husband were "a joke."

Soon after Fonseka's arrest on Feb. 8, government officials went public with various allegations against him, including that he plotted to assassinate Rajapaksa and capture power. But they are not among the official charges.

Fonseka's supporters have denied the charges brought against him, saying the government is punishing the retired general for challenging Rajapaksa and is attempting to cow the opposition before April 8 parliamentary elections.

Rajapaksa and Fonseka were once strong allies in their campaign to defeat the Tamil Tiger rebels and end their 25-year armed campaign for an independent state.

After routing the rebels last May, both were hailed as heroes by the country's Sinhalese majority. But they quickly turned on each other. Fonseka quit the army, challenged Rajapaksa in the Jan. 26 election and lost by 18 per cent.

The military has barred reporters from attending the proceedings, and is refusing to release detailed accounts about the case.

Wiith files from CBC News