The first confirmed case of swine flu in Asia was recorded in Hong Kong Friday after a Mexican man who arrived via Shanghai tested positive, Chief Executive Donald Tsang announced.

"We have our first confirmed swine flu case in Hong Kong. He is Mexican," Tsang told reporters.

The 25-year-old Mexican arrived in Hong Kong on Thursday from Mexico via Shanghai on China Eastern Airlines flight 505.

He was admitted to hospital on Thursday night suffering from a fever and tested positive on Friday for swine flu. He was in stable condition, Tsang said.

Health Secretary York Chow said guests and staff at the Metropark Hotel in Wanchai district where the Mexican had been staying will be quarantined for seven days.

"We have also exercised the authority... so that we will first isolate the hotel and also... ensure the relevant people are quarantined for seven days," Chow told reporters.

"We will also prescribe Tamiflu for them, which is proven to be an effective prophylactic for this disease."

He said around 200 people would be affected by the quarantine order, issued under the control and prevention of disease ordinance.

Hong Kong authorities were also trying to find the two taxi drivers who were in contact with the man, as well as passengers who flew with him on China Eastern flight MU 505 from Shanghai.

"We are also tracing the passengers who were on the same flight as this patient, particularly the three rows in front and three rows behind," Chow said.

"We're prepared to have them sent to hospital for inspection and also for quarantine," he said

Other passengers and crew would also undergo health checks.

"With this I hope that we can minimise the spread of this possible virus to our community," the health secretary said.

Despite putting the city on the highest level of alert, Tsang said all social activities and exhibitions would go ahead as normal and schools would remain open.

"I stress we don't need to panic," he said.

Police wearing face masks cordoned off the Metropark Hotel and a group of blue-gowned and masked health workers was seen entering the hotel in the bustling bar and nightclub district on Hong Kong island.

Hong Kong had already stepped up its protection measures, including the use of temperature screening machines at airports and other entry points.

Authorities have said they would detain anyone showing symptoms of the virus after arriving from an infected area.

Health officials have also advised against all non-essential travel to worst-hit Mexico.

Hong Kong, at the forefront of the SARS epidemic in 2003 and already on alert for bird flu, has announced a series of tough measures to combat any threat from swine flu.