Nearly 80,000 police and soldiers have been deployed across the Indian Ocean island to guard polling stations, where voters will decide who from among 7,620 candidates will serve in the 225-member parliament.

Rajapaksa has already parlayed last May's victory over the Tamil Tiger separatists into a new six-year term, and is now banking on a resurgent economy and political momentum to give his United Peoples Freedom Alliance (UPFA) a legislative majority.

More than 14 million people were registered to vote at polling stations that open at 7 a.m. Campaigning has been calm by Sri Lankan standards, with one death and 340 violent acts reported.

The end of the electoral uncertainty is expected to bring some stability to Sri Lanka's post-war landscape, and give way to a clearer picture of what Rajapaksa plans to do with a US$42 billion economy billed as an upcoming frontier market.

The central bank this week reported GDP growth of 3.5 percent last year, and forecast 6.5 percent this year.

Rajapaksa's alliance has positioned itself as the shepherd of island-wide development and an economic revival, propelled by a stock market that has gained more than 150 percent since 2009 and foreign investment in government securities.

With the rupee currency on the rise, bond dealers say they expect steady foreign demand for government securities of 18 months' tenure or less to pick up, especially after the vote.