SEOUL (AFP, REUTERS) - South Korea's parliament was shut down on Thursday (Aug 27) and a group of lawmakers were in self-quarantine as the country recorded more than 400 new coronavirus infections.

The South endured one of the worst early outbreaks of Covid-19 outside mainland China before bringing it broadly under control with extensive tracing and testing, but is now battling several clusters mostly linked to Protestant churches.

Thursday's 441 new cases were mostly in the greater Seoul area and are the latest in a series of near-six-month highs after several weeks with numbers generally in the 30s and 40s.

The National Assembly was closed after a photojournalist who covered a ruling party meeting on Wednesday was later confirmed to have contracted Covid-19.

The result prompted more than 10 top Democrats - including the party chairman and its parliamentary leader - to undergo tests and go into self-isolation.

After the meeting the reporter learned that a relative he had met at the weekend had tested positive, and he then had himself tested.

Officials on Wednesday held late-night talks on how to handle the situation and ordered all parliamentary activities suspended from Thursday, with both the assembly and a building housing lawmakers' offices closed.

Opposition parties also cancelled scheduled meetings.

The photographer came in contact with around 50 people at the assembly on Wednesday, 32 of them party lawmakers and officials.

The parliamentary shutdown is the second over coronavirus concerns, after a February closure when an attendee at an event tested positive.

Thursday's infection numbers were the 14th consecutive day of triple-digit increases and brought the country's total to 18,706. The death tally is now 313.

The high daily figures have prompted the country to urge businesses to have employees work from home, as it also flagged the risks of new clusters at call centres and logistics warehouses.

While authorities said the recent surge has mostly to do with recent outbreaks in a church and at an anti-government rally earlier this month, they warned about the possibility of new clusters in densely-populated workspaces.

"Please carry out thorough checks of risk factors at workplaces, where the work environment is especially vulnerable to infection, such as call centres and logistics warehouses,"said Health Minister Park Neung-hoo on Thursday.

"To reduce transmission within workplaces, please reduce the number of staff through flexible work hours, work from home and working staggered hours."

In March, South Korea reported a call centre outbreak, while at least 100 cases were linked to a logistics centre run by e-commerce giant Coupang Corp in June.

Mr Park said at least 80 per cent of the infections over the past week are from the densely populated Seoul metropolitan area and many were linked to the church and political rally.

A total of 933 infections have been traced to the church outbreak, Korea Centres for Disease Control and Prevention (KCDC) said.

Health authorities meanwhile have sent a list of at least 51,000 people, who have been categorised to be linked to the rally on Aug 15, to local governments, health ministry official Yoon Tae-ho told a briefing.

The jump in novel coronavirus cases come as the government is pushing for a healthcare reform, which has sparked opposition from doctors, prompting strikes.

Health authorities are now floating the possibility of imposing the highest level of social distancing, where schools and business would be urged to close, inflicting more damage on Asia's fourth-largest economy.