South Koreans vote on Wednesday for a new parliament, widely expected to give conservatives the majority that new President Lee Myung-bak needs to push through his plans for sweeping change to revitalize the economy.
Opinion polls suggested Lee's Grand National Party (GNP) will win at least 160 seats in the 299-seat assembly, with the left-of-centre United Democratic Party lucky to muster 100.
"It's not 180 seats or 200 seats we want. All we ask for is 150 seats plus one or two," GNP chief Kang Jae-sup told followers on Tuesday. "And then President Lee, who was elected to get the job done, can feel free to get the job done."
If all goes as predicted, the conservatives would win an outright majority in a parliamentary election for the first time in more than 20 years.
Lee, who took office in February, has pledged to boost economic growth this year to 6 percent from 5 percent last year, cut the red tape stifling business and make the economy more open and competitive.
Communist North Korea has turned up the heat, and on the eve of the election, branded Lee a traitor, saying his demands for the impoverished state to change its ways were pushing the Korean peninsula back to war.
But voters, accustomed to years of anti-South rhetoric, appear to have ignored the latest barbs from its irritable neighbor in a campaign that has been largely devoid of debate on any serious issue.
A National Election Commission poll showed turnout could be the lowest in the country's 20-year history of democratic elections with just half the electorate bothering to vote.
Turnout in the first few hours was down from marks posted at the same time of day in the last parliamentary election four years ago. Polls close at 6 p.m. local time.
To lure voters to the polling booths, the commission is running an advertising campaign featuring a popular song-and-dance group of teenage girls, and offering discounts to museums and parks.
But the once-predicted victory of two-thirds of the parliamentary seats, enough to change the constitution, looks unlikely. Lee has seen his initial high support slip as his government stumbled out of the blocks and bungled personnel appointments.
The damage from a global downturn began to look far more serious for South Korea just as he took office, with some analysts calling his economic growth target far too optimistic.
Some analysts said GNP infighting in the run-up to the election could make the party, even with a majority in the new National Assembly from late-May, tricky for Lee to manage and ensure his policy changes are turned into law.