THE UK Energy Minister has demanded retailers do not raise petrol prices after Opec agreed yesterday to cut oil production.

That must not be used as an "excuse" to push up pump prices, said Mike O'Brien.

The cartel announced it was cutting output by 1.5 million barrels a day, a move the government branded "disappointing". But Mr O'Brien insisted the action should merely "steady" the international oil price after sharp falls.

"We don't want to see retailers using any excuse to increase fuel prices. There's no need to do that," he said.

The minister said Britain had started to see the "benefits" of lower oil prices over recent weeks, with petrol now 96p per litre in some areas.

He urged consumers to "punish" garages with high prices by making sure they bought fuel from cheaper forecourts.

"At this point more than any other we need some benefits," said Mr O'Brien. "There is precious little good news going out the drop in the oil price over recent weeks has been something that could be helpful to the economy."

Yesterday's cartel meeting was brought forward by three weeks, reflecting the 12-nation group's concern at slumping prices. A statement read at the end of the meeting said prices had suffered a dramatic collapse, unprecedented in speed and magnitude.

Crude oil has tumbled to under $70 a barrel amid global recession fears - less than half the $147 high seen in July.

That has led to falling petrol prices at UK forecourts. Supermarket giants Asda, Morrisons, Tesco and Sainsbury's all recently announced new rounds of cuts.

Asda said yesterday it would hold its current prices for 10 days despite Opec's decision, and urged other retailers to do the same.

The retailer's trading director, Darren Blackhurst, said: "We hope petrol retailers don't use Opec's decision as an excuse to raise prices at the pumps. If they do, it would be blatant profiteering on their part.

"Instead we'd urge our rivals to follow our lead and lock down prices for at least the next 10 days. It is important we give drivers some certainty in these uncertain times.

"With world oil prices set to jump around over the next few weeks, we are guaranteeing to freeze prices at the pumps."

Mark Duffell, spokesman for Morrisons, said the chain had led the way in pushing pump prices down. He added: "Our customers know we follow refined oil prices. Any falls there, we can pass on to customers."

A spokeswoman for Tesco would not be drawn on how the company would react to the Opec decision, other than to say: "We will always look to pass on savings to our customers."

No-one from Sainsbury's was available for comment. BP refused to say how it would react to Opec's decision.