SEOUL (REUTERS) - South Korea's capital Seoul and its neighbouring regions will delay by a week the relaxation of social distancing rules due to a sudden increase in Covid-19 cases, authorities said.

The government had said it would relax social distancing and allow private gatherings of up to six people in the greater Seoul area, from the current four, starting on Thursday (July 1) as the country's inoculation drive has been picking up speed.

While the number of daily new infections have remained below 700 since early this month, South Korea reported 794 new coronavirus cases on Tuesday, according to the Korea Disease Control and Prevention Agency (KDCA).

Of the 759 new locally transmitted cases, 631 or 83.1 per cent were from the greater Seoul area, Mr Yoon Tae-ho, a senior health ministry official, told a briefing on Wednesday.

The cases, including the more transmissible Delta variants, were found in universities, workplaces and restaurants in the metropolitan area, Mr Yoon said.

Application of the revised social distancing in the current situation of "severe and critical crisis" may lead to further confusion and more transmission, Seoul city officials said in a statement.

Experts said the announced relaxing of restrictions, including longer operation hours for pubs and easing of the private gatherings ban, may have sent the wrong signal to the public and health authorities called on the public for caution.

South Korea has inoculated close to 30 per cent of its 52 million population with at least one dose of Covid-19 vaccine, putting it on track to meet a target of 70 per cent by September.

The country had registered a total of 156,961 infections and 2,018 Covid-19 deaths as of Tuesday midnight, KDCA data showed.