The political conflict may affect the Thai tourism industry if the situation prolongs until the first quarter of next year.
So far, no cancellations of air tickets and hotels have been reported among tourists heading to Bangkok and areas with major attractions.
After anti-government protesters put more pressure on the government by marching to 13 places in Bangkok and occupying the Finance Ministry on Monday, the Association of Thailand Travel Agents (ATTA) expressed its worries about the situation and called for a peaceful end to the political problems soon.
News and photographs of the protests were distributed by international media agencies.
Nineteen countries have issued travel advisories for their citizens to avoid visiting areas near protests in the capital.
The travel warnings came from Britain, France, Sweden, Japan, Taiwan, Canada, Austria, Israel, Brazil, Singapore, Belgium, the Netherlands, Norway, Germany, Hungary, Spain, Finland, Italy and Slovakia.
The Ratchaprasong Square Trade Association insists the Bangkok Countdown 2014 will be held at CentralWorld as planned. Tourists visiting the area are slightly down but the decline is expected to be short-lived.
But Prime Minister Yingluck Shinawatra said the occupation of the Finance Ministry by protesters could hurt investor confidence and undermine tourism.
Sugree Sithivanich, deputy governor for marketing communications at the Tourism Authority of Thailand (TAT), said its overseas offices had reported no trip cancellations to Thailand, though offices in Europe have yet to send their reports.
TAT believes that if the situation remains peaceful until the end of this year, tourism will not be affected and the target of tourist arrivals and income next year will remain intact.
If travel advisories reach Level 5 and tourists are banned from visiting Thailand, the number of visitors this year will drop by 8-10% to 25.75 million and tourism revenue will fall by 25 billion baht.
If Level 5 continues to the first quarter of next year, arrivals will increase by 7% next year compared with the 13% projection and tourism revenue will rise by 13% as planned.