The government and car makers are being urged to lower the prices of hybrid vehicles if they really want to promote the segment and cut fuel imports.
Prof Yossapong Laoonual, of the engineering faculty at King Mongkut's University of Technology Thonburi (KMUTT), said prices of hybrid and electric vehicles in Thailand are more than double those of similar models now available in the US, Britain and Japan.
Most hybrid cars are imported, and car makers have set their own prices due to limited competition in the segment.
KMUTT research shows most Thais still prefer to buy standard cars despite the expense of buying fuel.
The government has waived tariffs on imported hybrid auto parts such as batteries.
``The government should be more aggressive in promoting hybrid and electric cars in the short and long term,'' said Prof Yossapong.
JD Power Asia-Pacific Automotive Forecasting said hybrids accounted for only 20,000 of 1.43 million vehicles sold in Thailand last year.
Without government support, sales of hybrids are estimated to reach only 58,000 by the end of 2021 out of expected domestic sales of 2.5 million vehicles.
The government is being urged to offer tax waivers for hybrid imports in the short term and and more tax incentives to auto firms to stimulate investment in the sector.
If hybrid cars accounted for 15% of accumulated car sales in Thailand, it would save 1.26 billion litres of imported fuel oil worth 31.6 billion baht and cut greenhouse gas emissions by 7.98 million tonnes, KMUTT's research found.