Shenzhen has reported its first case of a human infected with the H7N9 strain of bird flu.

Authorities said a 38-year-old man from the city was confirmed on Wednesday to be carrying the virus.

The patient, who went to a clinic on Dec 9 for treatment for a cold and cough, has been admitted to Shenzhen No 3 People's Hospital in severe condition.

It is the fourth case of human H7N9 infection in Guangdong province in five days, China Central Television reported.

Six people have been infected with the virus in the province since August, the Guangdong health department said.