The increases would raise oil prices to another record high, with octane-91 and octane-95 prices increasing by 40 satang per litre to Bt27.14 and Bt27.94, while diesel would rise to Bt26.29.

A source in the retail oil business said global price rises had squeezed marketing fees for retailers to about 20 satang per litre, from the normal Bt1.50. It was planned to raise the retail price today, but the action was halted as the biggest retailer, PTT, chose to wait.

Chaiwat Choorit, senior executive vice president of PTT, said the company needed monitor the situation to decide when to raise prices. "The marketing fee is now at a very low level," Chaiwat said.

Higher oil prices would increase costs but yesterday cooking-gas producers agreed to maintain the gas price while the Energy Policy and Planning Office said it would delay the price floatation, scheduled for July, until a new government was formed.

Under the agreement with gas producers, the retail price of 15kg of cooking gas will remain at Bt265 and a 48kg container at around Bt820, said Siripol Yodmuangcharoen, director-general of the Internal Trade Department.

Dr Ampon Kittiampon, the secretary-general of the National Economic and Social Development Board (NESDB), said while most people were focusing on the political crisis, observers had overlooked external factors like rising oil prices.

Prices have been hovering above US$59 (Bt2,290) per barrel for three months, against an average of $49 in 2005.

"Higher oil prices affect inflation," he said. "We would need to accelerate measures to save energy or find alternative sources of energy to reduce oil bills.

"We also keep a close watch on global markets, particularly the US double deficits. This has forced the US rate to rise recently to rein in domestic consumption," he added.

Ampon said the planning authorities were concerned that the political crisis might damage the continuity of the country's economic policy and overseas investment, which was vital to maintain growth.

He said caretaker Prime Minister Thaksin Shinawatra had mentioned oil prices at the Cabinet meeting yesterday, and had instructed all agencies to monitor the situation.

The NESDB has maintained its economic growth forecast at 4.5-5.5 per cent and at the end of April the Bank of Thailand will determine if its 4.75-5.75 per cent forecast needs adjustment.

On Monday, world oil prices rebounded on the uncertain outlook for Iranian and Nigerian supplies, with futures climbing above $67 a barrel in New York and London.

Yesterday, the prices dipped as traders continued to take gains from a recent rally. Brent crude for May fell to $66.20 a barrel on London's intercontinental futures exchange.

On Monday, octane-95 refined petrol rose $1.1 to $74.92 per barrel while refined diesel went up by 70 cents to $78.01 per barrel.