COLOMBO - Sri Lanka's president has asked the top court to rule on whether he can seek a third term after the opposition insisted his snap re-election bid was illegal, officials said Wednesday.

President Mahinda Rajapakse has sought an urgent Supreme Court ruling on his decision to contest a third term in early elections expected in January 2015, a court document seen by AFP shows.

Rajapakse removed the two-term limit on the presidency soon after winning re-election in 2010. But opponents argue the amended constitution only applies to new presidents and cannot be used retroactively.

In an unusual move the Supreme Court has asked the influential Bar Association, with 11,000 lawyer members, to give a legal opinion within 48 hours. Rajapakse wants a final decision by November 10.

"We have already made our written submissions and we have also asked for an opportunity to make oral submissions in open court," said Bar Association chief Upul Jayasuriya.

Rajapakse's information minister let slip last month that the country was planning to head to the polls in January.

Official sources said Rajapakse had been hoping officially to announce his re-election bid after completing four years of his current six-year term on November 19, a day after his 69th birthday.

Rajapakse's court bid comes after he sacked the chief justice early last year and appointed his former attorney general and legal adviser to the post, with powers to interpret the constitution.

Rajapakse won popularity among Sri Lanka's majority Sinhalese community in 2009 by crushing rebels who had waged a 37-year war for a separate homeland for ethnic minority Tamils.

But his party's vote share plummeted at local elections in September, suffering its worst performance since Rajapakse came to power in 2005.

Rajapakse cut taxes and increased salaries, subsidies and welfare spending in a populist budget last month aimed at winning votes ahead of the polls.

The president is also under intense international pressure to probe allegations that his troops killed up to 40,000 Tamil civilians while battling Tamil rebels in the final stages of the war.