South Korean health authorities reported on Wednesday 7,175 new COVID-19 cases from the previous 24 hours, the biggest single day jump since the pandemic began early last year.

The tally included 7,142 local transmissions, more than 5,000 of which were from the greater Seoul area, and 33 cases imported from abroad.

Meanwhile the death toll rose by 63 to 4,020.

The number of critically ill coronavirus patients in ICUs reached yet another fresh high of 840, up 66 from the previous day.

The country has been battling a sharp spike in new infections since it began easing social distancing rules last month under its "living with COVID-19" campaign.

In the midst of this surge, the emergence of the new Omicron variant has compounded threats to public health.

The KDCA said the variant was detected in two more COVID patients, raising the total number of Omicron cases to 38.

Earlier in the week, the government reimposed caps on private gatherings and expanded the vaccine pass system to more multi-use facilities, urging people to cooperate with the national vaccination campaign.

More than 80 percent of people in South Korea have so far been fully vaccinated against the virus, according to the KDCA.