South Korea will extend its prevention and sanitation guidelines against the coronavirus until daily new infections drop to single digits, the health minister said on Friday, failing which he warned of a return to tough social distancing measures.

The announcement came as such cases persist in the mid-double digits following a series of new clusters in the area around Seoul, the capital, with 56 new cases on Thursday taking the national tally to 12,003, and 277 deaths.

Authorities will review whether to return to intensive social distancing if daily infections hover in that range, Health Minister Park Neung-hoo told a briefing.

"These guidelines are aimed at cutting the series of infections centered in the Seoul area that could result in a return to social distancing," he said.

More than 96% of new infections were in the Seoul metropolitan area in the last two weeks, he added. Of Thursday's new cases, 42 were from the Seoul area.

South Korea has limited gatherings and recorded every visitor to eight high-risk facilities, such as nightclubs and bars, since May 29, Park said.

Tough social distancing rules will be considered if 50 daily infections persist for more than two weeks, depending on the number of new outbreak clusters, Park added.