The Centre for Food Safety has banned the import of poultry and poultry products, including eggs, from Stanislaus County in California.
The ban was imposed after the centre was notified by the World Organisation for Animal Health about an outbreak of low-pathogenic H5 avian influenza on a quail farm in the county.
The centre has contacted American authorities and will monitor the situation.
About 150,000 tonnes of frozen poultry meat, eight tonnes of chilled poultry meat and 600 million poultry eggs were imported to Hong Kong from the US last year.
