The main conservative opposition United Future Party (UFP) and its satellite party were forecast to secure a total of 97 seats.

Turnout was 66.2 per cent, higher than any parliamentary elections held in the South since 1992.

Just a few months ago scandals over power abuse and sluggish economic growth threatened the left-leaning president, with critics calling his dovish approach towards North Korea – despite Pyongyang’s abandonment of its nuclear and ballistic missile test moratoriums – unrealistic.

But the South’s relatively quick and effective handling of the epidemic – it has also exported test kits to at least 20 countries – has been a boon for Moon ahead of the parliamentary elections, largely seen as a referendum on his performance.

And his so-called “coronavirus diplomacy”, such as recent publicity on his bilateral phone calls with at least 20 state leaders regarding epidemic response, boosted Koreans’ confidence in his administration, said Minseon Ku, a politics scholar at Ohio State University in the United States.

She added that the leader has been successfully framing the pandemic as an “opportunity for South Korea to restructure its economy, capitalising on industries like AI and biopharma”, and this “coupled with South Korea’s global recognition” for its handling of the outbreak sat well with the voters.

South Korea was among the first countries to hold a national election during the pandemic, with citizens still being asked to maintain social distancing after enduring one of the worst early outbreaks of the virus.

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All voters were required to wear protective masks, clean their hands with sanitiser and don plastic gloves, and undergo temperature checks on arrival at the polling station. Those found to have fevers cast their ballots in separate booths that were disinfected after each user.

The absolute majority win means Moon is likely to be less of a lame duck than previous presidents toward the end of their single five-year term.

“It should give his administration greater momentum,” said Andrew Yeo, a politics professor at the Catholic University of America.

Meanwhile UFP heavyweights former prime minister Hwang Kyo-ahn and ex-parliamentary floor leader Na Kyung-won failed to be re-elected.

The conservative party had “failed to rebrand” itself after the impeachment of former President Park Geun-hye, which “limited the boundary of support to older generations and core support regions”, said Ji Yeon Hong, a professor at Hong Kong University of Science and Technology.

But while the pandemic took public attention away from the opposition’s criticisms, it would be “dangerous” if Moon interprets the election as “vindicating foreign policies that aren’t working”, said Leif-Eric Easley, a professor at Ewha University in Seoul.

“Seoul’s engagement of Pyongyang has been met with diplomatic insults and missile tests. Placating China has yielded little benefit,” he said. “Talking tough on Japan has not advanced South Korean interests. And progressives want to accelerate military command reforms and resist cost-sharing pressures in Seoul’s alliance with Washington.”