Sri Lanka's former army commander, retired general Sarath Fonseka, appeared before a military tribunal Tuesday on charges of high treason, defence authorities said.

Military spokesperson Major General Prasad Samarasinghe said Fonseka faced seven different charges including leaking sensitive military information to the opposition, and questionable arms procurements that benefited his son-in-law.

The alleged offences were said to have taken place when Fonseka was head of the Sri Lankan army during the conflict with the Liberation Tigers of Tamil Eelam (LTTE) rebel group.

The former army commander attended the proceedings along with his counsel at the naval headquarters in the capital Colombo, Samarasinghe said.

The opening proceedings lasted nearly four hours as the charges were read out, before the next hearing was set for April 6.

The government also claims that Fonseka planned a coup, intending to assassinate President Mahinda Rajapaksa and take power.

Fonseka has vehemently denied the charges and has accused the government of a political witch-hunt against him and his supporters.

The former army commander was arrested Feb 8 and has been detained since at a naval base in the Sri Lankan capital.

Fonseka led the final military offensive that defeated the LTTE rebels in May last year.

Two weeks after the rebels' defeat Fonseka was told to step down from the army commander's position to take the post of chief of defence staff. The perceived demotion to a more ceremonial posting led to a falling-out with President Mahinda Rajapaksa.

Fonseka then contested the Jan 26 presidential elections as the candidate of an opposition alliance. He received only 40 percent of the vote, while incumbent Rajapaksa's 58 percent returned him to power for a second term.

Fonseka has said he would stand in the parliamentary elections scheduled for April 8. After the dissolution of the alliance that supported him in January, he is set to contest April's parliamentary elections under his own Democratic National Alliance, backed by the leftist Janatha Vimukthi Perumana or People's Liberation Front.

The People's Liberation Front was involved in two failed uprisings against the government in 1971 and during the 1987-90 period, in which an estimated 60,000 people perished. The party is currently leading the political campaign on behalf of Fonseka's candidacy.