The leader of Sri Lanka's main opposition Ranil Wickremesinghe has announced his presidential bid in the country's next presidential election on Sunday.

At the 50th annual convention of the main opposition United National Party (UNP) held here Sunday, the UNP endorsed the candidature of Wickremesinghe despite a dispute over whether the election would be held in 2005 or 2006 is yet to be resolved by the Elections Commissioner.

The debate on the dates for the next presidential election surfaced earlier this year when Kumaratunga's office did not deny press reports that Kumaratunga in late 2000 had been sworn in for her second term in a secret ceremony, therefore, her term ends only in December 2006.

However, the UNP said Kumaratunga must hold elections by December 2005, six years after the last presidential election was held in December 1999.

Meanwhile, the incumbent President Chandrika Kumaratunga who is on her second tenure cannot contest a presidential election a third time, but she is keen to amend the constitution to pave way for the return to Westminster style of governance from the present executive presidential system.

Wickremesinghe, a former prime minister, was unsuccessful in his first presidential election bid and was defeated by Kumaratunga in the last presidential election held in December 1999.

Two years later Wickeremesinghe was elected Prime Minister after his party defeated Kumaratunga's party in the parliamentary election, but his government came to be short-lived as Kumaratunga dismissed it and called a snap election in April this year.

Wickremesinghe pioneered the ongoing Norwegian-backed peace process with the Tamil Tiger rebels. His government held six rounds of direct negotiations before the process came to be stalled in April 2003.