Without specifying the exact tally, Health Minister Park Neung-hoo said on Thursday it was the first time it exceeded 500 since March 6, when South Korea battled the first major COVID-19 epidemic outside China.

The government re-imposed tough social distancing rules on the capital Seoul and surrounding regions this week after the daily numbers began hovering above 300 new coronavirus cases last week.

Authorities have warned the current wave might be tougher to control than earlier infections as most of the second wave has occurred in offices, schools, gyms and small gatherings in the wider general community around Seoul.

Park also expressed concerns that the rate of confirmed patients in their 20-30s had spiked to 28 per cent of total cases over the past month.

"COVID-19 has arrived right besides you and your family," he told a meeting.

"We're in a situation where it is not strange at all if anyone contracts the virus during our daily lives."

Australian Associated Press