The Association of Thai Travel Agents said tour operators have shifted tourism destinations to Bangkok's suburban areas and Pattaya.
Hotels in Bangkok will prepare vans to service their customers around the clock, especially for taking guests to airports, said president Sisdivachr Cheewarattanaporn.
The Tourism and Sports Ministry will set up a main help centre for foreign tourists at Hua Mak Sports Complex, together with small centres at key spots such as Don Mueang and Suvarnabhumi airports, Siam Center, Hua Lamphong railway station, and Ekamai and Phaya Thai skytrain stations.
Kajorn Weerajai, the ministry's deputy permanent secretary, said the Professional Tourist Guide Association of Thailand will offer 50 volunteers to help tourists at the centres.
"International tourists who cannot travel outside Thailand eight hours after their flight schedules due to the protests can claim US$100 compensation per day through the Thai Hotels Association," he said.
Anti-government protesters will gather at seven locations across Bangkok next Monday _ the Government Complex on Chaeng Watthana Road, Victory Monument, Lumpini Park, Lat Phrao, Pathumwan, Asok and Ratchaprasong.
Tourists staying in hotels near Ratchaprasong intersection are expected to be badly affected.
Centara Grand at CentralWorld hotel plans to stock enough food and drinking water for one month, up from one week normally.
Thirayuth Chirathivat, chief executive of Centara Hotels & Resorts, said the hotel will operate as usual but the number of guests should be smaller next week.
"Most Mice [meetings, incentives, conventions and exhibitions] reservations at our hotel this month have been postponed. This affects accommodation bookings as well. Occupancy in January is estimated at about 50%, compared with 80% in January last year," he said.
He expects the hotel's mid-sized Mice events to rebound within three months, while big events will take at least one year to recover after the protest ends. But domestic Mice events will bounce back quickly in about one month.
Mr Thirayuth said although Centara Grand will be affected by the mass rallies, the company's other hotels in resort destinations are still enjoying 80-90% occupancy this month.
Sumet Sudasna, president of Thailand Incentive and Convention Association, said many events organised for the first quarter in Bangkok have been cancelled due to the prolonged demonstrations.