Apichart Sankary, managing director of AED Travel, said if the political turmoil drags on until August, Thailand's tourism industry in the peak season will be damaged as the uncertainty sways tourists to try other destinations.
"We are quite worried now. Since the middle of last month, big foreign travel agents have no longer promoted package charter flights to Thailand," he said.
Tourism in Bangkok has been hit hardest as tour operators have tended to encourage customers to go to other destinations such as Pattaya, Rayong and Hua Hin.
However, tourism officials argue that the number of charter flights from Scandinavia has been gradually falling for several years because of numerous factors including political unrest.
In 2013, tourist arrivals from Denmark fell 2.14%, Finland was down 12% and Sweden decreased 7.37%. Only Norway saw a rise, by 4.3%. The negative momentum remained through the first quarter except for Finland, which rebounded to rise 15%.
The Tourism Authority of Thailand (TAT) predicts that tourist arrivals from Scandinavia will contract this year.
Tanes Petsuwan, TAT director for Europe, Africa and the Middle East, said 90% of arrivals from the region were repeat tourists, so the market had become saturated, but TAT plans to improve the situation through several campaigns.
Thailand is expected to record its lowest growth rate for tourist arrivals in five years because of the political chaos.
Sugree Sithivanich, deputy governor for marketing communication at TAT, said if the protests continue until the end of the year, tourist arrivals will rise only 1% to 26.7 million, far lower than the projected 28 million, and revenue from tourism will grow only 3% to 1.24 trillion baht, lower than the forecast of 13% growth to 1.32 trillion baht.
In the first four months of this year, Asian visitors to Thailand dropped by 11%, but European tourists increased by 6.64% to 2.25 million and American visitors rose 5.08% to 330,000.