Analysts say South Korea's relatively quick and effective handling of the coronavirus epidemic was a boon for the incumbent government ahead of the vote, largely seen as a referendum on its performance.
South Korea's left-leaning ruling Democratic party was heading towards a parliamentary majority in Wednesday's general election, exit polls showed, as voters backed President Moon Jae-in's handling of the coronavirus epidemic.
A survey by national broadcaster KBS projected the Democratic Party and a sister organisation would win between 155 and 178 seats in the 300-member National Assembly, while MBC and SBS also predicted it would secure an absolute majority.
The main opposition United Front Party and its sister grouping were expected to take between 107 and 130 seats, according to KBS.
The country uses a mix of first-past-the-post and proportional representation, and while the Democratic party was the largest in the outgoing parliament it did not hold a majority, relying on minority support to pass legislation.
Turnout was at least 63.8 percent, the highest since 2000.
Moon's position was not at stake as he is directly elected, but just a few months ago he was being assailed by critics over sluggish economic growth and his dovish approach to nuclear-armed North Korea.
But analysts say South Korea's relatively quick and effective handling of the coronavirus epidemic was a boon for the incumbent government ahead of the vote, largely seen as a referendum on its performance.
"With the virus spreading to other countries and South Korea receiving a relatively good evaluation in comparison, the epidemic has become an advantage," said Hahn Kyu-sup, a communications professor at Seoul National University.
Once grappling with the first large outbreak outside China, South Korea has largely managed to bring its cases under control without major disruptions thanks to a massive testing campaign and intensive contact tracing.
The Korea Centers for Disease Control and Prevention reported 27 new coronavirus cases on Tuesday, bringing the total infections to 10,564.
The daily tally has hovered around 30 over the past week, most of them from overseas travellers.
But authorities have warned that infections could resurge at any times, calling for special caution on Election Day.
As of 1200 GMT (9 am), voter turnout was 8 percent, about 0.9% points higher than in the last parliamentary election in 2016, according to the National Election Commission.
That excludes nearly 27 percent of the 44 million registered voters who took part in early voting last weekend.
Among them were about 2,800 coronavirus patients, for whom the NEC allowed voting by mail and set up special polling stations for early voting.
More than 13,000 in self-quarantine have signed up to vote and will be allowed to do so after other voters leave at 2100 GMT (6 pm local time).
The election campaign has taken on a different look, with candidates wearing masks and bumping fists instead of pressing the flesh and mass rallies.