Fewer than 10% of the first-time car buyers under the government scheme will likely cancel their bookings, a proportion unlikely to affect the automobile industry, says the Thai Automotive Industry Association.
President Piengjai Kaewsuwan said cancellation of bookings or requests for extending the delivery period are normal and faced by every dealer.
Some 1.3 million car buyers have taken advantage of the government's scheme, an initiative offering tax rebates of up to 100,000 baht for first-time buyers purchasing specific passenger cars and pickup trucks.
But buyers must keep the title to their vehicle for at least five years or else repay the tax rebate.
Under the scheme, many dealers offered potential customers deposits as low as 2,000 baht just to book.
Ms Piengjai said eco-cars are expected to be the segment hardest hit by booking cancellations, given their relatively cheap prices starting at only 380,000 baht.
Thailand is expected to make 2.5 million vehicles this year _ 1.3 million for local sale and 1.2 million for export.
The country enjoyed a bumper year in 2012, producing almost 2.45 million vehicles, a 68.3% jump from 2011 and lifting Thailand to 10th place among the world's car producers.
Of the total, 957,623 (39%) were passenger cars, 582 buses of more than 10 tonnes and 1.49 million trucks.
A total of 3.14 million motorcycles were made, up by 6.57%.
Domestic sales totalled 1.43 million vehicles last year, up by 80.9%, while motorcycle sales rose reached 2.13 million units, up by 6.11%.
Car exports increased by 39.6% to 1,026,671 vehicles, the most since the country began shipments in 1988, making Thailand the world's seventh-largest car exporter.