"I think OPEC has made an effort - we shall see if it is enough or not," the head of energy policy at the European Union's executive arm told Reuters on the sidelines of a conference in Brussels.

"They have made an effort and they have committed themselves that if it isn't enough they are ready to increase production more and they have committed to a band of prices," she said.

The Organisation of the Petroleum Exporting Countries (OPEC) agreed on Sunday to raise production of crude oil by 800,000 barrels per day from October 1, but the move did little to calm soaring oil prices.

West European countries have been swept by protests over high fuel prices this week with road hauliers and others calling for government action such as tax cuts to help ease the financial pain rising fuel costs are causing. In the face of blockades of roads, ports and refineries by hauliers, the French government said it would reduce tax on truck fuel by 15 percent. Neighbouring governments have thus far resisted popular calls to follow suit.

De Palacio said she was firmly against lowering tax, which the Commission believes would ease the pressure on oil producers to increase production and would also be counter to environmental aims by encouraging increased use of fossil fuels.

"There are some sectors which are more affected by the price and I think member states can take action to reduce the level of impact, but in no case, in my opinion, is the answer to reduce taxes," De Palacio said.