Chinese authorities have quarantined more than 70 apparently healthy Mexicans who they believe may have swine flu, Mexico's ambassador to Beijing said Sunday.

Jorge Guajardo said their citizens were being unfairly confined as none of them had any symptoms of the flu.

In response, China says the steps it has taken are lawful and justified as it does not want an outbreak in its heavily populated country.

Some 400 people have been quarantined in China since the virus was confirmed in a man who arrived from Mexico.

Nearly 50 Mexicans who had flown in from the United States have also been quarantined in Beijing, Shanghai and Guangzhou, he said.

The Mexican ambassador was denied access to a group being held at a Beijing hotel.

In many cases we have gotten reports that they were being quarantined for the sole fact that they had a Mexican passport, whether or not they came from Mexico, whether or not they had been in Mexico, whether or not they had been in contact with someone else from Mexico, Guajardo said, according to the Telegraph.

Meanwhile, around 300 guests and staff have been under quarantine t the hotel in Hong Kong, where a Mexican affected by the fever stayed for a night. Authorities have said they will remain in the hotel for seven days to ensure the disease does not spread to the city, according to Xinhua news agency. A25-year-old male Mexican has been found to have swine fever after he arrived in Hong Kong via Shanghai from Mexico.

Chinese Ministry of Health spokesman Mao Qunan said extra protection was needed after the virus reached Hong Kong.

The confirmation of this case clearly raised the risks of A-H1N1 flu entering our country, he said, quoted by state media.

He said the ministry had ordered for all those in close contact with the virus to be put under protective control.'