The group, which also includes travellers from the United States, Britain and several other countries, has been isolated in a hotel in the border town of Zhangmu for observation since Saturday.

The quarantine was imposed after an Italian woman, who was part of the group, was found having a fever during an Influenza A (H1N1) check at the Nepal-Tibet border. The 42-year-old woman has been taken to a hospital for tests and is still a suspect case for now.

The group had been on an eight-day tour of Tibet, and many planned to leave Nepal's capital Kathmandu on Saturday.

No one else has shown symptoms of the flu.

China's Health Ministry said in a news release yesterday that it was informed by Tibetan health authorities of the case only earlier yesterday, and had subsequently informed the countries involved.

Singapore's Ministry of Foreign Affairs said it has been in touch with the Singaporeans and has been rendering them necessary consular assistance.

It is not known how long they will remain in quarantine. One of the tourists, Ms Anna Husarska, told Agence France-Presse that things were 'completely inefficient'.

'First, we had to wait for half a day for the ambulance to come and pick us up. Then, they took us to this hotel, and we had to wait for a day and a half for the doctor to arrive,' she said.

China yesterday confirmed its fourth case of the H1N1 flu - a 59-year-old man who was stopped when he tried to enter south China with a fever last Friday on a train from Hong Kong.