The country added 1,347 more COVID-19 cases, including 1,334 local infections, raising the total caseload to 334,163, according to the Korea Disease Control and Prevention Agency (KDCA).
The daily number of COVID-19 cases has stayed in the quadruple digits since July 7.
Health authorities are worried about a possible surge in confirmed cases as more cases are expected to be reported in the coming days after the extended weekend.
The prolonged weekend ended Monday, a substitute holiday for Hangeul Day on Oct. 9, which celebrates the proclamation of the Korean alphabet.
The country added 11 more deaths from COVID-19, raising the death toll to 2,594. The fatality rate was 0.78 percent.
Since the country began its inoculation campaign on Feb. 26, 40 million people, or 77.9 percent of the population, have received their first shots of COVID-19 vaccines, the KDCA said.
The number of fully vaccinated people stood at 30.6 million, or 59.6 percent.
Starting on Tuesday, additional vaccine jabs will be given to about 45,000 medical workers who were fully vaccinated six months ago, the authorities said.
Of the locally transmitted cases, Seoul reported 482 new cases, with Gyeonggi Province that surrounds the capital city reporting 411 cases and Incheon, 40 kilometers west of Seoul, reporting 81 cases.
The greater Seoul area has been under Level 4 measures since mid-July, the highest level of the country's social distancing rules, which includes a ban on private gatherings of six people, including two who have been fully vaccinated, after 6 p.m.
The number of new imported cases came to 13, unchanged from the previous day. The accumulated total of imported cases is now at 14,737.
The number of patients with serious symptoms across the country reached 364, down from 371 the previous day, the KDCA said.
The total number of people released from quarantine after making full recoveries came to 299,260, up 1,238 from a day earlier. (Yonhap)
