COLOMBO: Sri Lanka's government said Tuesday that it would challenge the legitimacy of leading opposition candidate Sarath Fonseka, who contested the country's first post-war presidential election.

"We are seeking a court order on the suitability of this candidate because he is not eligible to be declared as a candidate," Foreign Minister Rohitha Bogollagama told reporters.

He said they would seek court action to have Fonseka ruled out of the race after the former four-star general was unable to vote in Tuesday's election because his name was not on the electoral list.

Responding to suggestions from ruling-party lawmakers that Fonseka could be disqualified, the country's independent election commissioner gave the opposition figurehead resounding backing in a statement earlier Tuesday.

"Not having one's name on the electoral list is not a disqualification," Dayananda Dissanayake said.

Bogollagama said the government would challenge this assessment.

"What the election commissioner has expressed is merely an opinion, but the courts have the ultimate authority to interpret the law," Bogollagama said.

Asked if it was premature for the government to press legal action even before the results of Tuesday's vote were declared, Bogollagama said they were acting within their rights.

"We can challenge the candidacy of even a defeated candidate," Bogollagama said. "We are not saying that he will emerge the winner. We are confident we will win, but we want the court to rule on his candidacy."

He said Fonseka deceived the 14.08 million electorate. "He asked the electorate to vote for him and did not disclose that he himself did not have a vote," Bogollagama said. "This is deception."

Another candidate had in December wrongly challenged Fonseka's candidacy on the basis that he was a US citizen. The objection was rejected by the elections chief.

Fonseka has said he holds a US "green card" which gives him the right to live in the US.

There was no immediate comment from the opposition, but opposition leader Ranil Wickremesinghe said on Monday that the government may try to hold onto to power if President Mahinda Rajapakse was defeated in his re-election bid.

The opposition has also warned that the government may use the military to stage a coup and deprive Fonseka of a victory, a charge denied by the government.