Prime Minister Kim Boo-kyum said during a virus meeting the country could be forced to take "extraordinary" measures if the surge doesn't slow soon.

Officials issued administrative orders requiring hospitals around the country to designate a combined 2000 more beds for COVID-19 treatment.

Kim said the government will also speed up the administration of booster shots by shortening the interval between the second and third vaccine injections from the current four or five months to three months starting next week.

Around 41.5 million people, or 81 per cent of the population of over 51 million, have been fully vaccinated, but only 10 per cent have received booster shots.

The Delta-driven spread in recent weeks has been accompanied by a spike in hospitalisations and deaths, many among people in their 60s or older whose immunities have waned after being inoculated early in the vaccine rollout that began in February.

Officials tightened restrictions starting on Monday, banning private social gatherings of seven or more people in the greater capital area and requiring adults to verify their vaccination status at restaurants and other indoor venues.

But Kim said such measures haven't yet showed an effect in slowing transmissions.

"If it becomes clear that we aren't succeeding in reversing this crisis situation within the next few days, the government will have no other choice but to employ extraordinary anti-virus measures, including strong social distancing," said Kim, South Korea's No. 2 behind President Moon Jae-in.

The Korea Disease Control and Prevention Agency said around 5300 of the 7022 new cases reported on Friday were from capital Seoul and the nearby metropolitan area, where the virus has hit hardest.

South Korea has 63 confirmed Omicron cases.

The country's death toll is now at 4130 after 53 virus patients died in the past 24 hours, while 852 others were in serious or critical conditions.

Australian Associated Press