South Korea reports 34 new coronavirus cases, highest in a month

South Korea reported 34 new coronavirus cases on Sunday, the highest daily number in a month, after a small outbreak emerged around a slew of nightclubs that a confirmed patient had visited.

Of the new cases, 26 were domestically transmitted infections and eight were imported cases, the Korea Centers for Disease Control and Prevention (KCDC) said.

Sunday's total was the highest since April 9. After battling the first major epidemic outside China, South Korea posted zero or very few domestic cases over the past 10 days, with the daily tally hovering around 10 or less in recent weeks.

The resurgence followed a small but growing coronavirus outbreak centred around a handful of Seoul nightclubs, which a man in his late 20s had visited before testing positive for the virus.

At least 15 people were traced to that man as of Friday, and 14 of the 26 cases were reported from Seoul on Sunday, although the KCDC did not specify how many were linked.

The outbreak prompted Seoul city to impose an immediate temporary shutdown of all nightly entertainment facilities on Saturday. The city said it is tracking down abut 1,500 people who have gone to the clubs, and has asked anyone who was there last weekend to self-isolate for 14 days and be tested.

The outbreak came just as South Korea has eased some social distancing restrictions and is seeking to fully reopen schools and businesses in line with a transition from an intensive social distancing campaign to what it calls "distancing in daily life."

President Moon Jae-in warned of a second wave of the epidemic later this year, saying the recent cluster underscored the risks that the virus which causes COVID-19 can spread widely again at any time.

"It's not over until it's over. While keeping enhanced alertness till the end, we must never lower our guard regarding epidemic prevention," he said in a televised speech marking the third anniversary of his inauguration.

"We are in a prolonged war. I ask everyone to comply with safety precautions and rules until the situation is over even after resuming daily lives."

Widespread testing, intensive contact tracing and tracking apps have helped Asia's fourth largest economy largely contain the epidemic without extensive lockdowns seen elsewhere.

As part of a long-term battle on COVID-19, the KCDC will be given greater power and renamed the Disease Control and Prevention Administration, Moon said. Local governments will set up their own epidemic response system with more experts.

"We will also push to establish hospitals specialised in treating infectious diseases and a national infectious disease research centre," Moon said.

"These tasks are very urgent if we are to prepare for the second epidemic wave that experts predict will hit this fall or winter."