The threat comes amid reports that prices of liquefied petroleum gas (LPG) and natural gas-fuelled (NGV) are set to rise.
Mr Withoon will file a petition to the transport and justice ministries, requesting the use of energy credit cards for drivers of LPG-powered taxis. Currently, only NGV-fuelled taxi drivers are allowed to use energy credit cards.
The rise in gas prices will affect operators of about 80,000 taxis, he said.
The drivers of NGV-powered taxis currently pay 8.50 baht per kilogramme on gas because they are entitled to a discount of 2 baht per kg from the credit cards, he said.
The network will have no choice but to increase fares if their demand is not met, he said.
Asdsathai Rattanadilok Na Phuket, director-general of the Land Transport Department, said the transport and energy ministries will hold talks to discuss measures to deal with the problems of taxi service providers.
Speaking about the prospect of a taxi fare hike, he said the department has assigned the National Institute of Development Administration to conduct a feasibility study on solutions.
The study will consider factors such as fuel prices, traffic conditions and the number of gas stations, Mr Asdsathai said. If the study concludes that a fare hike is needed, a suitable rate will be considered, he said, adding that the findings of the research should be published this month.
Meanwhile, goods transport businesses are planning a 5% price increase in November to ease the cost burden of the new 50.5 tonne weight limit on large lorries.
Yu Jianyuenyongpong, president of the Land Transport Federation of Thailand, said transport prices will not go up immediately because operators have to consider factors including supply and demand for goods shipments.
"It is expected that demand for goods transport will rise in November as we enter the harvesting season for farm output, when the need for cargo lorries is substantial," Mr Yu said. "That is the appropriate time to raise prices."
The transport cost for farm products will rise to between 1.10-1.20 baht per kilometre and 1 baht per km for industrial goods, he said.
Mr Yu said the transport cost per unit has risen since the 50.5 tonne lorry weight limit was imposed in July. He also noted that transport operators are still unable to send their cargo to a number of Asean countries because no agreement is in place to allow lorries across borders.