South Korea's new coronavirus cases stayed above 20,000 for the second consecutive day Sunday amid growing concerns about a resurgence in infections nationwide.

The country added 20,410 new COVID-19 infections, including 250 from overseas, bringing the total caseload to 18,511,845, the Korea Disease Control and Prevention Agency (KDCA) said.

The KDCA reported 19 more deaths from the virus, putting the death toll at 24,643. The fatality rate stood at 0.13 percent.

The number of critically ill patients came to 67, up from the previous day's 61.

South Korea has seen a marked drop in infection numbers from the peak of more than 620,000 in mid-March, with the daily counts staying mostly in four digits in June.

But the numbers began to rise again, hitting over 10,000 on June 29 and over 20,000 on Saturday.

Health authorities confirmed that the country has entered a new wave of COVID-19, citing the fast spread of the highly contagious mutation of the omicron strains.

The government is reportedly considering a new set of antivirus measures. (Yonhap)