World oil demand growth is set to flag next year in line with a slowdown in the global economy, even as supply from non-OPEC countries is seen increasing, the Organization of Petroleum Exporting Countries said in its monthly oil market report Wednesday.

The producer group forecast that oil demand growth will slow to 0.8 million barrels a day in 2013, but said supply from non-OPEC members will outpace this to grow by 0.92 million barrels a day compared with this year.

Oil demand growth is expected at 0.9 million barrels a day in 2012.

Demand for OPEC crude is seen falling by 0.3 million barrels a day to 29.6 million barrels a day in 2013, below the group's current production levels, suggesting that the world will be well-supplied in the coming year despite increasingly tight sanctions that are affecting the supply of Iranian oil.

However, the group highlighted "considerable uncertainties" still facing the market that could affect this forecast in coming months, with
U.S. and European demand presenting the biggest risks to growth even as emerging markets push for higher consumption.

"The unsteady pace of the global economic recovery is causing a considerable uncertainty for world oil demand," said OPEC, adding that emerging markets are expected to drive global oil demand next year.

Based on the significant risks facing the global economy, OPEC said oil demand growth could reach as much as 1 million barrels a day next year in the event of strong demand growth in the
U.S. , improvements in OECD Europe's economies and a serious recovery in Japan . However, it said that a much smaller growth rate of just 0.65 million barrels a day was also possible if the global economic recovery slowed and high prices affected demand.

OPEC's own production declined last month to 31.36 million barrels a day, according to secondary sources. Iranian production fell the most, declining 188,500 barrels a day to below 3 million barrels a day in June, leading up to the full ban on the Islamic Republic's exports imposed by the European Union July 1.

Disclosures from OPEC members showed Saudi Arabian output bounced back above 10 million barrels a day last month, despite concerns from other member states over the steep drop in oil prices seen in June.