The exercise, coded "Tai Shan," tested a joint effort by 14 organizations like the Airport Authority Hong Kong, the Department of Health and other related government departments and airlines under the monitoring of observers from the Chinese mainland and overseas.

The five-hour exercise started at about 1:00 AM Friday and simulated an arriving Cathay Pacific flight carrying 56 passengers and five crew members.

As part of the exercise, the airline reported that a sick passenger was onboard the flight, suspected to be suffering from avian flu symptoms. As the sick passenger was considered to be a possible human case of avian flu, the aircraft was isolated and disinfected, while passengers and crew members were put under quarantine by the Department of Health.

The Airport Emergency Center was immediately activated to coordinate contingency procedures. While the sick passenger was transported to Princess Margaret Hospital for isolation and treatment, other passengers and crew members were escorted to designated isolation areas for further assessment and subsequent management.

"Recent human cases of avian flu reported in the region near Hong Kong indicate that the disease remains a threat to public health," said Howard Eng, Airport Management Director of the Airport Authority.

"Therefore, we must remain vigilant against the possible occurrence and spread of infectious diseases at the airport," he said, adding the exercise offered an opportunity for all relevant parties to practice the airport's contingency procedures and collaborative responses in the event of an avian flu incident.

In separate event, the Agriculture, Fisheries and Conservation Department announced here Friday afternoon that an Oriental magpie robin, a common resident bird in the city, found dead earlier in Tai Po was confirmed to be H5N1 positive after a series of laboratory tests.

The bird carcass was found and collected on Feb. 29 near the management center in Tai Po Kau Nature Reserve in northwest of Hong Kong.