BANGKOK - THAI Prime Minister Somchai Wongsawat warned on Saturday that the kingdom risks being isolated from the international community if protesters do not retreat from Bangkok's airports.

The five-day siege by anti-government demonstrators has caused 30,000 passengers a day to miss flights, costing the top tourist destination millions of dollars a day and prompting global appeals for action.

'To lay siege to the airports is extremely dangerous. It will make foreign countries lose confidence in Thailand. They will not fly their aircraft in or allow their citizens to travel here,' Mr Somchai told reporters.

Mr Somchai himself has been holed up in the northern city of Chiang Mai since Wednesday, as the blockade forced the diversion of his flight from a summit in Peru.

The government says he will remain in Chiang Mai indefinitely due to tensions with the army, which has denied that it is planning a coup.

The premier said he had instructed his Interior Minister Kowit Wattana to map out measures to disperse the protesters at Suvarnabhumi international airport and the smaller Don Mueang domestic hub without violence.

'I assigned Kowit to draft procedures for transparency, to ensure that law enforcement officers do not violate any laws, by inviting human rights commissioners and the media to witness (the police actions),' he said.

But his initiative was quickly rejected by the chief of the National Human Rights Commission, Saneh Chamarik, on the grounds that their presence could be seen to legitimise the use of force by police.

'To invite the commission to observe at Suvarnabhumi means we will be witnesses, which we do not want,' Mr Saneh told a news conference.

Mr Somchai said his government remained open for negotiations but 'not on condition of resigning and dissolution (of parliament),' which the opposition People's Alliance for Democracy had demanded.