Energy Minister Pongsak Raktapongpaisal has instructed relevant agencies, state enterprises and energy firms to provide accurate information to the public to avoid confusion about the fuel price structure.
His order came after two anonymous Facebook groups posted messages and tables of retail fuel prices that he said were misleading or downright untrue.
Their purpose is most likely to discredit energy policymakers, said Mr Pongsak.
One Facebook post alleged Thailand has its own crude oil resources, raising the question of why oil must be imported.
"Thailand's retail oil prices are higher than in Malaysia and Indonesia because PTT and the Energy Ministry are looting us," read another post. "PTT and the Energy Ministry set retail oil prices that are not based on global market prices."
Mr Pongsak yesterday said he has known of the messages for many weeks as thousands of internet users followed and joined the groups.
"I assigned our legal department to look at ways to tackle these anonymous groups misleading the public," he said.
Mr Pongsak insisted the Energy Ministry sets fair prices for petrol users, but the state Oil Fund must shoulder the cooking gas subsidy.
He also denied claims that the ministry is overreacting to an expected natural gas disruption from Myanmar next month in order to weaken opposition to coal-fired power plants.
"Coal is the most viable option in Thailand and the last resort to diversify fuel in electricity generation," he said.
Meanwhile, the ministry yesterday conducted an emergency response drill for the likely gas disruption in early April.
The rehearsal was intended to improve monitoring and emergency management systems.
"We are prepared for the worst-case scenario that gas from the Gulf of Thailand drops at the same time as supply from Myanmar," said Mr Pongsak.