SEOUL (REUTERS) - South Korea's daily Covid-19 cases topped 3,000 for the first time on Saturday (Sept 25) as an outbreak fuelled by a three-day holiday this week continued to grow.

The country reported 3,273 Covid-19 cases for Friday, a day after hitting the previous high, the Korea Disease Control and Prevention Agency (KDCA) said on Saturday.

Of the new cases, 3,245 were locally transmitted and 28 were imported, bringing South Korea's total to 298,402 infections with 2,441 deaths.

More than 77 per cent of the domestically transmitted cases have been in Seoul and areas neighbouring the capital, where about half the nation's 52 million people live.

"We estimate that the surge in travel during the Thanksgiving holiday, as well as the increase in person-to-person contact, could be major reasons for the sharp increase," said the agency's director, Jeong Eun-kyeong.

The current outbreak of the highly infectious Delta variant has contributed to the jump in infections, she told a briefing.

Daily infections may continue to surge over the next one or two weeks, she added, urging people to delay or cancel private gatherings over the period.

The mortality rate and severe cases remain relatively low and steady at 0.82 per cent and 339, respectively, helped by vaccinations that prioritised older people at high risk of severe Covid-19, KDCA said.

The number of coronavirus tests jumped more than 50 per cent to 227,874 from a week earlier, according to the KDCA.

The authorities have advised people returning from this week's three-day holiday to be tested even for the mildest Covid-19-type symptoms, especially before going back to work.

The daily caseloads may continue to surge and peak by next week as more people get tested after the break, deputy minister of health care policy Lee Ki-il told a briefing on Friday.

South Korea has given 73.5 per cent of its 52 million population at least one dose of Covid-19 vaccine through to Thursday (Sept 23), and has fully inoculated nearly 45 per cent.