BANGKOK, Nov 28, 2008 (AFP) - An estimated 90,000 passengers have missed flights since protesters shut down Bangkok's airports, the tourism minister said Friday, and emergency centres will be set up to help them.

"Around 90,000 passengers are estimated to have been unable to leave Thailand from November 26 to 28," tourism minister Weerasak Kowsurat told AFP after a crisis meeting with airlines.

"Most foreign travellers including tourists who suffered from the closure of the airports are still in Thailand."

The main Suvarnabhumi international airport has been shut since late Tuesday when anti-government protesters besieged it.

Weerasak said that 7,000 travellers were stuck at the airport when it was raided, more than double the figure given by airport authorities at the time.

They were taken to hotels on Wednesday, and are among the tens of thousands of travellers trying to get out of the kingdom.

Weerasak said the ministry would open information centres at four Bangkok hotels, where airlines could set up desks and travellers could reschedule flights, get new tickets and check in.

"The plan for these centres is already approved in principle and expected to start operating at four hotels in Bangkok in the next 48 to 72 hours," he said.

"No big batch of travellers" had been able to leave through the U-Tapao naval base 190 kilometres (118 miles) southeast of Bangkok, he said, which has ferried a handful of passengers out but can only handle 48 flights a day.

Suvarnabhumi can handle 700 flights every day.

"The travellers had better wait at their hotels for further information because U-Tapao airport cannot cope with a large number of people," he said.

The government is in talks with coach companies to try and arrange mass transport down to the Vietnam War-era naval base, he added.

He said that immigration authorities had also agreed to extend the visas of all foreign tourists trapped and people will not face the usual fines if they overstay their visas.

Anti-government protesters late Wednesday also surrounded smaller Don Mueang airport, forcing its closure on Thursday, although it only handles some domestic flights.