AFP - Demand for oil is surprisingly strong as China and the United States lead global economic recovery, but rising oil prices and mysteries in the data could derail the trend, the IEA said on Thursday.

"The recent price spike, if further extended, risks derailing the recovery," the IEA warned.

And it stressed uncertainty in its estimates of how underlying forces in the oil market would work out.

This was partly because the oil market had undergone exceptional disruption at the height of the crisis, and because the effects of removal of government stimulus policies was unknown.

In addition, stocks of oil were high, and data was increasingly difficult to obtain from China where a withdrawal of stimulus and possible economic overheating could set back activity.

The report provided two figures which highlight questions over whether or not prices are disconnected from underlying forces.

Global demand rose to give an estimated average figure for 2009 of 84.8 million barrels per day.

But global supplies in October rose by 645,000 barrels per day to a higher figure of 85.6 mbd.

And OPEC is estimated to have spare capacity of 5.4 mbd.

Oil inventories held in OECD countries rose by 4.3 percent on a 12-month basis.

However, the latest data suggests "that global (oil) demand is well on track for resumed year-on-year growth in the fourth quarter of 2009, for the first time since the second quarter of 2008," the International Energy Agency said.

It raised its estimate for global oil demand this year by 210,000 barrels per day, and for next year by 140,000 barrels per day on the back of "surging demand in China and Saudi Arabia, as well as somewhat higher-than-anticipated data for the US."

The agency also highlighted in its monthly review of energy markets different viewpoints within the Organization of Petroleum Exporting Countries (OPEC).

Some "price hawks" wanted to reduce output further because stocks of oil in the market remained high.

However "there seems to be a quasi-consensus among others that an increase in output targets may be in the offing" if prices rose significantly.

"Saudi Arabia has unofficially branded 70-75 dollars a barrel as an ideal target price," for OPEC oil.

On Thursday, New York's main contract, light sweet crude for delivery in December, shed 41 cents to 78.87 dollars a barrel.

The IEA, the energy-policy arm of the OECD, observed: "OPEC members, especially in the Middle East Gulf, are worried that higher oil prices could threaten the global economic recovery."

However, demand in Europe "plummeted by 6.7 percent year-on-year in September, and in the overall Pacific region, oil product demand fell for the 15th month in a row, and by 6.1 percent on a 12-month basis.

Global oil demand in 2009 of 84.8 mpd was l.5 mbd or 1.7 percent less than in 2008.

Demand was expected to total 86.2 mbd next year, representing an increase of 1.3 mbd or 1.6 percent from demand this year.

The rate at which demand had shrunk was slowing down in the 30 leading industrialised countries covered by the Organisation for Economic Cooperation and Development. OECD demand may have peaked in 2005.

Meanwhile, "demand in non-OECD countries is exceeding expectations."

Demand in the 12 biggest consuming countries could be seen as proof that "the global economy is on the mend."

But the "modest" rebound came from a "very low base". This meant that "signs of renewed growth must remain tentative," the IEA warned.

For example, demand growth in China was driven mainly by demand for various oil products, and in Saudi Arabia by increasing use of basic crude oil to fuel power stations.

Production of oil for industry was a better guide to "sustained economic activity."

But global demand for gasoil (diesel), a vital factor in rail and truck transportation which underpins industry and trade, "remains subdued and should decline by 3.1 percent year-on-year in 2009."

The report warned: "Therefore, a leading indicator of a sustained economic rebound will arguably be gasoil demand."

Meanwhile, the IEA also raised its estimates for global oil supplies. Overall OPEC output rose by 110,000 bpd in October to 29.0 mbd from a low point of 28.1 mbd at the beginning of the year.

The 11 OPEC countries, excluding Iraq were now producing 1.6 mbd more that the target ceiling of 24.845 mbd.

And non-OPEC supply rose by 380,000 bpd in October to 51.4 mbd as maintenance work on North Sea installations ended.