SHANGHAI - New Orleans Mayor Ray Nagin, who had been due in Australia for a speaking engagement, instead remained in quarantine in Shanghai on Wednesday over a swine flu scare, his spokesman said.

Nagin, who was detained Sunday after a fellow passenger on his flight fell ill with a suspected case of swine flu, has missed several meetings in the Chinese business hub since being quarantined, spokesman James Ross told AFP.

"Mayor Nagin, his wife and executive protection staff are all doing very well. They are feeling fine and they have no symptoms of illness," he said.

"They remain in very good spirits and are simply looking forward to a speedy resolution."

Nagin was originally scheduled to leave Shanghai on Tuesday night for Australia where he was to give a speech on climate change at the University of Sydney on Thursday.

"We are waiting for guidance from Chinese medical officials and certainly he will leave when he is authorised to do so," Ross said without offering any specific date of departure.

"The mayor fully understands the focus of the medical authorities and has been treated with the utmost courtesy and just looks forward to moving on as soon as possible," Ross said.

China has submitted passengers to temperature checks and at times quarantine at its airports in a bid to stop the spread of swine flu. Those placed under quarantine have usually been released after a seven-day observation period.

The country's strict flu control measures have faced foreign criticism. On Tuesday, Chinese health authorities announced that mainland had more than 100 confirmed cases of the A(H1N1) swine flu virus.

China confirmed its first case of the illness - which has killed 139 people in six countries - on May 11, but it has so far recorded no deaths.

According to the latest data by the World Health Organization, 73 countries have reported a total of 25,288 cases.