Saynee Phoowasatethaworn, chairman of Ko Samui's Tourism Promotion, said both Thai and foreign tourists are now heading to Phuket because of lower air prices. He said letters of protest complaining about the hikes had been submitted to relevant ministries.

The rates were raised in October from Bt3,550 to Bt5,085 including the airport fee of Bt350 for executive class air tickets, and from Bt3,560 to Bt4,450 for economy class airport fee-included tickets.

Saynee said there would be around 10,000 joining the rally on Wednesday if the airline did not announce what it would do by today. The hikes have also badly affected tourism activities in other areas, including many nearby islands.

Ramnate Jaikwang, a member of the Surat Thani Provincial Administrative Organisation representing Koh Samui district, said Bangkok Airways violated its declaration document signed on March 26, 2004 that it would not raise ticket prices higher than Bt3,000 for high season and Bt2,500 low season.

Samui Airport director Sirichai Jaroenrat, a Bangkok Airways employee, said only 5 per cent of Thai passengers had been affected by the raise, which he said had now benefited 35 per cent of regular passengers based on the island from an original 20 per cent. He said air tickets for early- and late-night flights were still sold at Bt2,000.