The latest case was detected at a poultry farm in Hwaseong, Gyeonggi, which is raising 202 chickens and 67 wild geese, according to the Ministry of Agriculture, Food and Rural Affairs.
To prevent further spread, officials have taken measures to control access to the farm in order to carry out investigations and cull the affected chickens and wild geese.
The Gyeonggi provincial government plans to conduct inspections on 18 poultry farms in Gimpo, 38 kilometers (23.6 miles) west of Seoul, by Tuesday.