Four more public servants working at South Korea's main government complex in the administrative city of Sejong have been infected with the new coronavirus, city officials said Wednesday, sparking concerns over a potential cluster infection at the facility where 15,000 people work.

Three at the Ministry of Oceans and Fisheries in Sejong, 130 kilometers south of Seoul, were confirmed to have contracted the illness, according to the officials.

Another member of the oceans ministry was confirmed infected with COVID-19 a day earlier. The four worked in the same department.

The city officials said a civil servant from the Education Ministry was also identified as a virus patient earlier in the day.

So far, a total of 17 virus cases have been reported in the administrative city.

The Sejong government complex accommodates 35 government ministries and agencies.

Last week, a public servant working at the health ministry in Sejong was also infected with COVID-19.

South Korea's total virus cases numbered over 7,700 as of Wednesday. (Yonhap)