South Korea's new COVID-19 cases jumped to a weekly high of more than 80,000 on Tuesday amid concerns over the spread of a new omicron subvariant and a wintertime surge.

The country confirmed 81,056 new coronavirus infections, including 63 from overseas, bringing the total to 29,220,591, the Korea Disease Control and Prevention Agency said.

It is far higher than the previous day's 22,735, as the infections had been on a decline over the past six days. The figure a week earlier was 87,512.

The country added 29 COVID-19 deaths, bringing the death toll to 32,301. The death rate stood at 0.11 percent.

The number of critically ill patients came to 620, down from the previous day's 637. The figure surpassed 600 on Sunday for the first time in about eight months.

South Korea is watching the developments regarding the new omicron subvariant of XBB 1.5, which has been spreading rapidly around the world recently. Experts said the subvariant could be more infectious and resistant to immune response.

The KDCA has said the country first found an XBB 1.5 case on Dec. 8, and a total of 13 cases have been detected so far, including seven from overseas.

The authorities have also been stepping up efforts to minimize the impact of recent growth in the virus in China, as Beijing eased strict antivirus restrictions.

On Monday, South Korea began requiring a polymerase chain reaction test for arrivals from China within the first day of their entry.

They must remain in separate facilities here until their test results are confirmed, while South Korean nationals and foreigners with residency status returning here from visiting China have to quarantine at their residence after a polymerase chain reaction test.

Starting Thursday, those from China must show either a negative polymerase chain reaction or antigen test for the coronavirus before boarding flights to South Korea. They will be required to receive a polymerase chain reaction test within 48 hours before their arrival or an antigen test within 24 hours before their arrival.

Of the 63 imported cases reported Tuesday, 16 were from China, the KDCA said. (Yonhap)