Polling officers carrying ballot boxes walk with a police officer as they prepare to go to their polling centers ahead of presidential election in Colombo January 7, 2015. [Photo/Agencies]

COLOMBO - Voting started in Sri Lanka's presidential election on Thursday, which is tipped to be a close race with the incumbent president Mahinda Rajapaksa fighting for an unprecedented third term.

Long lines of voters were observed as polling stations were opened.

More than 14.5 million Sri Lankans are eligible to cast their votes at Thursday's polling.

Rajapaksa and New Democratic Front (NDF) candidate Maithripala Sirisena are the main contenders, though 17 others are also in the fray.

"I'm confident that the voting will be peaceful," Elections Commissioner Mahinda Deshapriya said ahead of the voting.

The Elections Department has put in place elaborate arrangements to ensure that the election is conducted smoothly while special security arrangements, including 71,000 policemen, have been assigned by the police and security forces.

There will be 1,400 counting centers across nation.