Vienna- One day before members of the Organization of the Petroleum Exporting Countries (OPEC) meet to discuss slashing production, the cartel said Tuesday that global oil demand would decrease in 2009, contributing to an overhang of stocks.

As industrialized countries slipped into a recession, global oil consumption would fall to 85.68 million barrels per day next year, a year-on-year decrease of 0.18 per cent, Vienna-based OPEC said in its monthly oil market report.

The figures stood in contrast to a forecast by the International Energy Agency (IEA) in Paris, which said last week that demand would grow slightly, by 0.5 per cent.

OPEC president Chakib Khelil has indicated that the cartel's oil ministers would decide on a substantial cut of production quotas when they meet in Oran, Algeria on Wednesday, in order to support falling prices and deal with lower demand.

As OPEC predicts falling demand and rising production from non-OPEC suppliers, it said stocks would grow in the first three quarters of 2009, creating a market imbalance that would be addressed in Oran.

In November, OPEC had still forecast global oil demand to grow by 0.57 per cent next year.

"Should the world economic situation show further deterioration and the winter prove to be warmer than expected, then oil demand might show a further decline," the report said. (dpa)