By Ranga Sirilal
COLOMBO (Reuters) - Sri Lankan President Mahinda Rajapaksa on Thursday called a presidential election, seeking an unprecedented third six-year tenure, but demands for his power to be curbed and a possible split in his vote base means re-election won't be a walkover.
Rajapaksa, 69, came to power in 2005 and won a second term in 2010 on a wave of popularity after the military defeated Tamil Tiger separatists, ending a 26-year civil war.
"I am declaring a secret today. I have signed the proclamation calling for the election for re-election for the third time... That is democracy," Rajapaksa said, addressing a gathering shown on state television.
An official at the Election Commission said polling would be held in early January.
Rajapaksa's rivals have yet to find a strong challenger. But critics, including his coalition partners, say Rajapaksa enjoys excessive powers under a system known as "executive presidency" introduced by a 1978 constitution that has given his family a tight grip on the economy and politics.
Several opposition lawmakers and government allies have said that many members of Rajapaksa's ruling United People's Freedom Alliance (UPFA) are considering defection to try to unseat him.
"We'll definitely defeat him if he doesn't abolish the executive presidency before the election," Athuraliye Rathana, a Buddhist monk and a legislator of Jathika Hela Unrumaya (JHU), a coalition partner in Rajapaksa's government and a hardline nationalist Buddhist party, told a public meeting last week.
Science and Technology Minister Champika Ranawaka, a JHU member, resigned on Tuesday but said his party was still open to discussions to remain in the Rajapaksa camp.
Rajapaksa will be banking on Sinhala Buddhists, who account for around 70 percent of the population, to re-elect him. But this vote base could be split because of a prominent Buddhist monk who opposes the executive presidency.
Maduluwawe Sobitha, who heads the National Movement for Social Justice, has brought together most of the opposition parties to agree on a common candidate and demand the abolition of the executive presidency within six months after the polls.
Rajapaksa has said he will abolish the additional powers after the election, but made the same pledge in 2005 and 2010.
In moves seen as wooing voters, Rajapaksa announced many handouts and salary hikes in the 2015 budget, and has harped in speeches on the war victory under his leadership in May 2009.
But Rajapaksa's popularity is fading: his party won a recent provincial poll, but with 21 percent less support than in 2009.
Many accuse him of nepotism, corruption and politicization of the judiciary and foreign services, charges his administration rejects.
(Writing by Shihar Aneez; Editing by John Chalmers and Nick Macfie)