A 500,000 bpd hike, equivalent to 2 per cent of Opec output, would come as no surprise to the international oil market as it will be automatically triggered by Opec's price band mechanism if prices stay above its $22-$28 per barrel target range. But Venezuelan officials expect a substantial increase in pressure to bring prices down to levels acceptable to the industrialised world, as the US enters the final stage of an election campaign and Opec prepares for a rare heads-of-state summit.

"Opec will not take automatic action a few days before the meeting," said a Venezuelan oil official who asked not to be identified. "In three weeks' time we have an Opec meeting and there they will take a decision. Some in Opec and outside will be pressing for more than 500,000 bpd," he added.

World oil prices are hovering around their highest levels in a decade as growing world demand faces limited supply from the cartel that controls two-thirds of world exports.

Opec's benchmark export basket price stood at $29.33 per barrel Monday, well outside the group's $22-$28 per barrel target range. The European Union contacted Venezuelan Opec president Ali Rodriguez Monday to voice concern over high oil prices and asked Venezuela to "moderate its stance".Venezuelan president Hugo Chavez made an unprecedented tour of Opec this month to rally support for an historic Opec heads-of-state summit next month and insisted that current prices were not high, but "fair".

If prices stay above $28 for the next three weeks, Rodriguez has insisted that Opec's target mechanism will automatically trigger a 500,000 bpd supply increase on Sept 8, just two days before the meeting scheduled in Vienna."Venezuela wants to follow the price band procedure, but I am not sure we will manage to convince the others, and the others means Saudi Arabia," another official said, who also asked to remain anonymous. "If Saudi Arabia says yes, then it goes ahead, but they do not want to be limited by automatic decisions," he added.

Opec kingpin Saudi Arabia has shown ambivalent support for the mechanism, preferring to talk of a $25 price target, and has consistently pushed the group for supply rises greater than 500,000 bpd in recent policy meetings.The price band mechanism was last triggered in June, but instead of going ahead with the prescribed increase, Opec chose to wait until its regular meeting and then decided on a 7,08,000 bpd rise. Those pushing for an increase greater than 500,000 bpd will point to so-called "secondary sources" that Opec uses to measure its own production, which indicate the cartel is already pumping 450,000 bpd on top of the group's 25.4 million bpd supply ceiling, excluding Iraq which is under the UN sanctions.