South Korean Prime Minister Kim Boo-kyum tested positive for the coronavirus on Thursday, his office said, as daily infections hit unprecedented levels this week, driven by the spread of the highly transmissible Omicron variant.

Kim has steered anti-virus efforts, holding regular meetings with officials and experts, and visiting medical and educational facilities to check quarantine work and promote vaccination.

"He was coughing a bit this morning but is now only having mild cold symptoms," an official at his office told Reuters.

He had begun receiving treatment at home and the intra-agency anti-virus meetings would be temporarily led by other officials, his office said in a statement.

The Korea Disease Control and Prevention Agency (KDCA) reported 198,803 new COVID cases as of midnight Wednesday, a day after the daily tallies hit a record of 219,241.

Daily deaths rose to a record 128, for a total of 8,394, and serious cases surged to 766, compared with about 300 two weeks ago.

South Korea has largely been a COVID mitigation success story, with 3,691,488 infections among its 52 million population and a relatively low death rate.

But health officials estimated that the current wave of infections will go on and peak at about 330,000 daily cases by mid-March.