Public opinion polls have predicted a resounding victory for the liberal-agrarian Centre Party leader Juha Sipila, a 53-year-old IT millionaire and newcomer to politics.
Polling stations across the country opened at 9:00 am, and were to close at 8:00 pm (1700 GMT) when the results of advance voting -- by which more than one-third of the electorate cast their ballots -- were to be released.
Campaigning heavily on his business know-how, Sipila has vowed to get the economy back on track after three years of recession and stagnation, austerity and failed reforms.
Elected to parliament in 2011, Sipila became party leader in 2012 when he was still virtually unknown to most Finns.
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In opposition since 2011, the Centre has recently been credited with around 24 percent of voter support.
If its victory is confirmed today, Sipila's first task will be to pick his coalition partners. Tradition dictates that the largest party takes the post of prime minister and forms a government with the other largest parties to obtain a majority in parliament.
Several weeks of thorny negotiations are expected before Sipila is able to present a coalition.
Three parties are fighting for second place, hovering between 14 and 17 per cent in the polls: Prime Minister Alexander Stubb's conservative National Coalition Party, the Social Democrats and the right-wing eurosceptic Finns Party.
Sipila has not revealed which parties he would like to see join his future coalition.
But he has insisted that the next government be able to cooperate smoothly to push through its policies -- contrary to the discord that has deadlocked Stubb's four-party coalition.