The South Korean government has detected cases of bird flu at 33 farms across the country in the past week, though it's unclear how many of the cases were caused by a highly pathogenic strain of the virus.

According to the Ministry of Agriculture, Food and Rural Affairs, poultry at six more farms tested positive for avian influenza as of Friday, including three farms in Imsil County. 

More tests are being run to determine if the birds are infected with the highly pathogenic H5N8 virus.

The ministry said an earlier reported case of bird flu in Busan has now been confirmed as H5N8.

According to the ministry, the H5N8 virus has been confirmed at 12 farms, including three on Jeju.