He developed fever and pneumonia on Feb 22 and died within nine days of hospitalisation.
Many people travel between Hong Kong and Guangzhou, heightening the risk of persons with the virus entering Hong Kong. Much of Hong Kong's chicken supply also comes from farms in this area.
The Centre for Health Protection (CHP) held an emergency meeting Friday, after being notified of the suspected case from the health officials in China.
The news prompted calls from lawmakers to tighten up border health checks on travellers and on poultry imports.
Hong Kong has had no human cases of bird flu in the current outbreak, but CHP director Leung Pak-yin warned that the threat was increasing.
"We expect there could be human cases in Hong Kong and we all need to be well prepared for that," he said.
Hong Kong witnessed the first-ever human cases of bird flu in 1997 when 18 people were infected, of whom six died. The outbreak was the first known instance of the virus jumping the species barrier.
Since then the territory has set up strict regulations on the farming and selling of chickens. These include vaccinating poultry at farms and regular clean-up days at markets.
In recent weeks, a number of wild birds have been found dead with the H5N1 virus heightening fears that Hong Kong will soon record its first human victim.