Three chickens found dead on Monday have tested positive for bird flu, prompting authorities to suspend poultry imports for 21 days and begin slaughtering 80,000 birds, a senior official said yesterday.

"We feel that Hong Kong is facing a new threat from bird flu," said York Chow, secretary for food and health.

The chickens, found dead at a farm with 60,000 birds, have been confirmed as having the H5 virus and further tests are being carried out to see if it was the H5N1 strain, he said.

The farm and neighboring poultry operations have been declared part of an infected zone, and about 80,000 birds in the area will be killed to prevent the spread of the disease, Chow said.

The 21-day ban on poultry imports will last through the Christmas holiday, a time when chicken is traditionally on the menu, he said.

Hong Kong's biggest bird flu outbreak came in 1997, when six people died after the H5N1 jumped from fowl to humans. In response, the government slaughtered all 1.5 million poultry in the city.

Authorities carried out a similar cull to eradicate a flu outbreak in 2001, killing 306,000 birds from markets and 951,000 from farms, Chow said.

There are currently about 600,000 birds left in the region, he said.

Since 2003, at least 245 people around the world have died from bird flu, according to figures from the World Health Organization.

The Hong Kong government has been encouraging retailers to stop selling live birds, and the majority of shops have given up their licenses to sell live poultry.

However, consuming fresh chicken is an important part of the local culture and many shoppers still demand freshly slaughtered birds.