The announcements came after representatives of 15 travel firms met yesterday to discuss contingency plans in light of the outbreak of Middle East respiratory syndrome.

The executive director of the Hong Kong Travel Industry Council, Joseph Tung Yao-chung, said initial health advice issued by the government on Monday had confused travellers and agencies about whether to cancel tours.

He said agencies had received a large number of inquiries from customers unsure whether the health advice meant they should or could apply for refunds.

"With only the health advice, tour agencies were not able to immediately promise refunds to tourists because the firms may not have been able to claim the money back," Tung said. "So now a red travel alert is a more effective move to help us."

However, Tung said cruise trips with stops in South Korea, such as in the coastal city of Busan 325km from Seoul, would go ahead, adding the decision to cancel lay with ship captains.

At the airport yesterday, no flights to Seoul had been cancelled, but some ground staff were spotted wearing face masks.

A Korean businessman in Hong Kong for three days said he had been monitoring news about the Mers outbreak. "I am not worried about it. I have to go back home anyway," he said.

Another traveller said he was taking a flight to the United States via Seoul.

"If it wasn't for the stopover, I would not go to Korea," the passenger said. "The outbreak sounds uncontrollable."

Cathay Pacific, which operates five flights a day to Seoul, has cancelled one of the flights effective throughout July and August.

Airline Route, a website that tracks global flight schedules, said flight CX434/438 to Seoul along with the return flight CX439 had been cancelled.

Cathay said the company and its subsidiary Dragonair would waive rebooking and rerouting fees for passengers going to Seoul, Busan and Jeju from now until the end of August, if their tickets were issued in Hong Kong.

"We are monitoring the situation closely and will continue to coordinate closely with health authorities in Hong Kong and in all the ports that we operate flights to," a Cathay spokesman said, adding frontline staff had been told to remain vigilant.

Hong Kong Express Airways had similar arrangements in place for flights to Korea.

The other two major airlines that operate flights to the country, Korean Air and Asiana Airlines, said there had been no changes to their flight schedules.

Lee Suet-ying, chairwoman of the Hong Kong Association of Secondary Schools, said about 10 local schools had cancelled study tours to South Korea.

But a member of the Hong Kong Ezra Ministry Institute, which has organised an 850-strong Christian fellowship trip to Seoul for the end of next month, said 80 per cent of those signed up still wanted to go.

The member said she wasn't worried about the outbreak, but said the organisation would monitor the situation closely.

Tung said the council would discuss with tour agencies later this month whether tours next month would be cancelled.

"If the outbreak shows no sign of easing by that time, I expect there will still be no tours," he said.