The mainland has reported the first ever human infection of the H7N4 strain of bird flu.
Hong Kong's health officials said their mainland counterparts notified them on Wednesday of the case.
The patient was a 68-year-old woman living in Liyang in Jiangsu province.
She came into contact with live poultry before becoming ill on Christmas Day last year, and was admitted to hospital on New Year's Day.
The woman was discharged after three weeks.
Health officials in Hong Kong called on the public to maintain strict personal hygiene when visiting any place with live poultry.