The move highlighted South Korea's desperate efforts to try to block the spread of a highly pathogenic strain of H5N8 that hit the resort island on Friday.

Separately, quarantine officials have already killed more than 144,000 poultry in Jeju following the latest outbreak of bird flu -- the first in two months in South Korea.

The culled birds accounted for about 8 percent of the total 1.67 million chickens and 43,000 ducks on the island.

Besides Jeju, quarantine officials have also slaughtered more than 30,700 poultry in several other cities, including Gunsan and Iksan, both located in the country's southwestern region, according to the Ministry of Agriculture, Food and Rural Affairs.

As of Wednesday, five suspected bird flu cases were confirmed to be a highly pathogenic strain of H5N8 while lab tests are underway to identify the AI strains in 13 other suspected cases.

On Monday, the officials said the five suspected cases from farms in the southern city of Ulsan and Yangsan were confirmed as the H5N6 strain.

Highly pathogenic bird flu refers to viruses that spread quickly and result in high death rates, according to the World Health Organization.

South Korea slaughtered more than 30 million poultry to contain the worst outbreak of bird flu that hit the country in November.

It was forced to cull 14 million birds in 2014. (Yonhap)