Hong Kong, Dec 31 (IANS): As many as 15,000 chickens will be culled in Hong Kong to prevent an outbreak of bird flu, authorities said Wednesday.

Authorities said the chickens at the Cheung Sha Wan market will be slaughtered following the latest discovery of the deadly H7N9 virus in poultry imported from south China's Guangdong province, Xinhua quoted Food and Health secretary Ko Wing-man saying.

A batch of chickens imported from Huizhou city in Guangdong province tested positive for the virus through a "rapid testing" programme.

The market will then be closed for 21 days for thorough cleansing and disinfection, Ko said, adding that trading of live poultry will be suspended during the closure period.

He said the government has built up a resilient and stringent system and collaborated closely with the mainland authorities for the surveillance and control of avian influenza.

Meanwhile, Hong Kong announced it was raising its response level in hospitals to "serious" from "alert" with extra precautions implemented from Sunday in response to a new case of the avian influenza virus -- the region's first since early 2014.