The government is considering imposing a lockdown at all poultry farms throughout the country as avian influenza was showing signs of further spreading, officials said Sunday.

A nationwide lockdown, if issued, will prohibit the movement of any poultry, workers or vehicles from farms for 48 hours. Such a move can be extended once for another 48 hours.

Such a move will create what health authorities here have called a "window of opportunity" to sterilize all poultry farms at the same time and thus prevent a further spread of the disease.

The consideration for such a move apparently comes as the animal disease is fast spreading to surrounding areas from Gochang in North Jeolla Province, where the first outbreak of AI was confirmed Jan. 17.

The government had imposed a 48-hour lockdown at all poultry farms in Gochang soon after the first outbreak of AI was confirmed.

The number of confirmed AI cases has since reached 18 with the highly pathogenic H5N8 strain of the virus confirmed in the latest case at a chicken farm in Buyeo, South Chungcheong Province on Saturday.

A new suspected case was reported earlier in the day at a duck farm in Cheonnan, located only some 80 kilometers south of Seoul, the Ministry of Agriculture, Food and Rural Affairs said in a press release.

Tests were under way in an additional 21 suspected cases as of Sunday.

Some 470,000 birds, mostly ducks, have been slaughtered so far.

Over 1.74 million others are set to be culled as the government has decided to also destroy chickens at all farms within 3 kilometers from affected farms after it confirmed the first outbreak of bird flu in chickens Saturday. (Yonhap News)