SEOUL (REUTERS) - South Korea will extend social distancing rules with a ban on private gatherings of more than four people in a bid to stamp out the possibility of a fourth wave of Covid-19 infections, Prime Minister Chung Sye-kyun said on Friday (March 12).

The announcement at a government meeting comes as South Korea has been ramping up its immunisation drive, authorising use of AstraZeneca's coronavirus vaccine for people aged 65 years and older in a bid to inoculate 70 per cent of its 52 million residents by September.

The country has administered 546,277 doses of Covid-19 vaccines as of Thursday midnight, the Korea Disease Control and Prevention Agency (KDCA) said, including both AstraZeneca and Pfizer-BioNTech treatments.

Mr Chung said the number of daily confirmed Covid cases has been frustratingly stagnant, hovering between 300 and 400 over the past eight weeks. The country reported 488 new Covid-19 cases on Thursday, the highest in three weeks.

South Korea has so far reported a total of 94,686 infections, with 1,662 deaths.

The Prime Minister warned of the constant risk of cluster infections in greater Seoul area, where the third wave began.

Over 60 per cent of infections were recorded in the capital and neighbouring areas, according to the KDCA.

"We are aware that the citizens are getting weary of drawn-out social distancing," said Mr Chung. "A retreat from virus-prevention measures could lead to a fourth wave of infections."