South Korea's daily new coronavirus cases stayed in the 600s for the third straight day Friday due to sporadic cluster infections as the country is set to implement eased social distancing rules starting next month.

The country reported 634 new cases, including 602 local infections, raising the total caseload to 153,789, the Korea Disease Control and Prevention Agency (KDCA) said.

Cluster infections involving churches, restaurants, education facilities and hospitals continue to take place across the country, raising concerns that eased distancing rules and potential spread of the new coronavirus variants may trigger further infections.

The country added one COVID-19 death, raising the death toll to 2,009. The fatality rate came to 1.31 percent.

The country is bracing for a potential uptick in the number of variant infections, especially the more transmissible Delta variant first detected in India.

South Korea has yet to report a large number of Delta variant cases, but other countries, such as Britain and the United States, whose vaccination rates topped 50 percent, have been struggling with rising cases of the variants, which are known to be more contagious than the original ones.

The woes over variant cases also came as South Korea is set to ease its social distancing scheme staring July 1 amid its vaccination drive, which allows businesses to stay open longer and permits gatherings of more people.

Currently, the greater Seoul area is under Level 2 distancing in the five-level scheme, while the rest of the country is under Level 1.5. Private gatherings of five or more are banned nationwide.

Under the new four-tier system, restaurants and cafes in the capital area will be permitted to operate until midnight under Level 2, an extension from the current restrictions of 10 p.m.

The nationwide ban on gatherings of five or more people will be lifted under the renewed guidelines, with the ceiling set to be raised to eight under Level 2. No restrictions are applied under Level 1.

In the greater Seoul area, the ceiling will initially be set at six people for the first two weeks of next month.

A total of 15.2 million people, or 29.6 percent of the country's 51.3 million population, have received their first shots of COVID-19 vaccines since the vaccine rollout in late February.

Of them, 4.5 million, or 8.8 percent of the population, were fully inoculated as of Friday.

The country aims to inoculate 36 million with at least one jab by September to achieve herd immunity in November.

Of the newly confirmed locally transmitted cases, 264 came from Seoul and 179 from Gyeonggi Province that surrounds the capital.

The southern port city of Busan added 27 cases. Incheon, just west of Seoul, added 24 cases, the southeastern port city of Ulsan added 16 cases, and Daejeon, 160 kilometers south of Seoul, added eight cases.

The number of patients in serious or critical condition came to 143, up two from the previous day.

The total number of people released from quarantine after making full recoveries was 145,389, up 601 from a day earlier.

South Korea has carried out 10.47 million COVID-19 tests, including 27,763 the previous day. (Yonhap)