UPDATE 3-World oil demand to strain supply in 2012-IEA

* IEA sees continued gap between OPEC output and demand for OPEC oil

* Maintains that strategic petroleum reserves release is working

* No decision yet on further stocks releases (Adds quote, further details)

By Alex Lawler and Barbara Lewis

LONDON, July 13 (Reuters) - World oil demand growth will accelerate next year, adding to the pressure on available supplies, the International Energy Agency said on Wednesday, contradicting a more conservative outlook from producer group OPEC.

In its first 2012 forecast in a monthly report, the IEA said oil use would grow by 1.47 million barrels per day (bpd) to 91 million bpd. The agency also trimmed its estimate of demand growth this year to 1.20 million bpd.

The IEA's 2012 prediction was more than the 1.32 million bpd expected by OPEC and lower than a forecast from the United States' Energy Information Administration. It expects all of the growth next year to come from emerging economies.

"Aside from economic growth, downside pressures from higher-than-expected oil prices also represent a risk to the forecast," said the Paris-based IEA, which advises 28 industrialised countries.

Differences between the Organization of the Petroleum Exporting Countries and consumer nations widened after the 12-member OPEC in June failed to reach a deal on a Saudi-led proposal to increase output.