It brought to 183 the total number of people diagnosed with MERS in the largest outbreak outside Saudi Arabia.
The latest case involved a nurse from Seoul's Samsung Medical Center, the health ministry said.
The hospital, which has so far accounted for almost half of all confirmed cases, declared a 10-day suspension of most health services last month to stem the spread of the virus.
As the hospital continued to report new cases, the shutdown was extended indefinitely.
Of the 183 confirmed cases, 33 have died, 102 have been cured and released from hospital and 48 are still being treated, with 12 of them listed as being in critical condition, AFP reported.