The outbreak was discovered after a dead chicken was found at the farm in the New Territories area of Hong Kong, near the border with China.
All chickens within a three-kilometre (1.9-mile) radius of the farm were slaughtered, local farms were barred from selling chickens and eggs for 21 days and imports of chickens were banned for the same period.
Hong Kong was the scene of the world's first reported major bird flu outbreak among humans in 1997, when six people died. Since then, H5N1 has killed more than 250 people worldwide.
Scientists fear the virus could mutate into a form which is much more easily transmissible between humans, triggering a global pandemic that could kill millions.
Sit said genetic analysis showed the virus was of the type commonly found in southern China, but added it could have come from anywhere in Asia.
Hong Kong's Health Secretary, York Chow, said the city needed to stay on full alert against avian influenza which posed an imminent worldwide threat.
"To help achieve such a task, the biosecurity measures of local chicken farms will be vital to minimise the risk of avian influenza," Chow said in a statement.
The role of wild birds in the spread of bird flu is not yet fully understood and many experts say they have been unfairly scapegoated as a distraction from the more pressing risks of intensive poultry farming.
Source-AFP
SRM