Opec President Purnomo Yusgiantoro said on Monday the producers' group would guarantee oil supplies to the market at times of high prices, but would still go ahead with a planned cut to production limits in April.
"Opec has an automatic adjustment on prices. When prices are above $28, Opec guarantees supplies," Purnomo told reporters, when asked what action Opec might take now that US crude is above $37 a barrel.
Asked whether Opec was ready to put more crude on to the market, he said: "Yes, we are ready to supply the market."
Purnomo, who is also Indonesia's oil minister, said the cartel would carry through an agreement to cut official production limits by one million barrels per day (bpd) from April 1.
"That we will do, there is no decision to review," Purnomo said.
Opec's decision to reduce production has been criticised by consumers, who are facing the highest prices since March last year when oil was bolstered by expectations of a US invasion of producing nation, Iraq.
US light crude was trading nine cents up at $37.35 a barrel at 0527 GMT on Monday, while London's Brent crude was 15 cents higher at $33.50 .
The deputy executive director of the International Energy Agency said on Monday high oil prices were hurting the economies of developing nations and Opec should resist trying to micro-manage the market.
"We would welcome a restoration of more normal stock patterns and flows and a little bit less effort to micro-manage, and let the market manage the ebbs and flows itself," William Ramsay said at an oil conference in Auckland, New Zealand.
"We are a little perplexed by the idea of a cut on April 1 as it really won't take effect in the market until some time in May or June, and we are going into the driving season when refineries are running flat out to meet gasoline demand," Ramsay said.