OPEC expects world oil supplies to remain ample during the northern hemisphere winter and keep a lid on oil prices, indicating the producer group is unlikely to make major changes to output policy at a meeting next month.

In a monthly report, the Organisation of Petroleum Exporting Countries (OPEC) left its forecasts for world oil demand growth in 2011 and 2012 unchanged. It has been steadily lowering its demand outlook this year, citing weaker economic growth in developed countries and efforts by China and India to curb fuel consumption.

OPEC, whose 12 members pump more than a third of the world's oil, said the recovery in output from Libya and increased North Sea output should add to supplies of high-quality crude oil, while weak demand in developed countries was keeping oil inventories at relatively high levels.

Taking all these developments together, this should ensure that the crude and product markets remain well supplied throughout the winter season and should limit any upward pressure on prices, OPEC said in the report, which is written by economists at its Vienna headquarters.

World oil demand will rise by 880,000 bpd this year and increase by a further 1.19 million bpd next year, OPEC said, unchanged from its previous monthly report.

(Reporting by Alex Lawler; Editing by Alison Birrane)