Deputy Prime Minister and Energy Minister Supattanapong Punmeechaow has rejected calls to divert profits from national oil and gas conglomerate PTT Plc to subsidise diesel prices.
The idea was part of a five-point proposal discussed by Democrat MP for Ratchaburi, Akaradech Wongpitakroj, at Thursday's House session, where Mr Supattanapong answered MPs' questions about high diesel prices.
Speaking in favour of the proposal, Mr Akaradech said the government should review the role of PTT and make it serve the public interest rather than just focus on making profits.
According to the Democrat MP, the energy giant recently posted a profit of 80 billion baht for the first three quarters.
He said it should set aside a chunk of its earnings to subsidise diesel prices.
Mr Supattanapong said even though the government holds a 62% share in PTT, it cannot use the company's profit to support government measures. He described such a move as illegal.
However, the minister said the energy firm pays taxes and dividends to the government, and that relief measures such as the government's oil fund are shored up by such revenue.
He insisted he was not just defending PTT's interests, noting the company's diesel prices reflected government policy and stressing it offers the cheapest diesel on the market.
Meanwhile, transport operators said the government's measure to address diesel prices was not good enough, even though it would bring the prices down under 28 baht per litre.
They were referring to the Energy Policy Administration Committee's (EPAC) decision to reduce the proportion of palm oil-derived methyl ester to 7% and postpone the 10% and 20% methyl ester-blended diesel from next month to March next year.
Next month, oil retailers will sell only biodiesel B, which will effectively lower diesel price in Bangkok and its vicinity to less than 28 baht a litre.
Apichart Prairungruang, chairman of the Land Transport Federation of Thailand (LTFT), said the most suitable price would be 25 baht. He said the government should consider further reducing the proportion of palm oil-derived methyl ester.
"We understand the government can't lower the excise tax," he said. "We'll come back for an answer on Dec 15."