
The boy from was admitted to hospital a week ago with convulsions after arriving from the southern Chinese city of Guangdong.
The Centre for Health Protection said the boy tested positive for the AH5 strain of bird flu.
More tests were being conducted to determine whether it is the deadly H5N1 sub-strain of the virus which has been responsible for 356 deaths since 2003, according to the World Health Organisation.
The patient was being treated in isolation and described as in stable condition.
Hong Kong saw the first modern outbreak of H5N1 bird flu infecting humans when six people died and 12 others were infected in 1997.//DPA