Oil demand from emerging countries this year will offset lower consumption by advanced economies in the OECD, the International Energy Agency said on Friday.

In its monthly report, the IEA said global demand growth would gradually accelerate throughout 2012 from close to zero growth in the first quarter to an expansion of 1.2 million barrels per day by the fourth quarter.

"Global oil consumption is set to rise by 0.8 million barrels per day in 2012, to 90.0 mbd, with gains in the non-OECD more than offsetting declining OECD demand," the IEA said.

The modest upside revision is attributable to marginally improved economic growth numbers provided by the International Monetary Fund, the agency said.

"The world's four biggest markets -- China, the US, Europe and Japan -- should dominate the demand story in 2012," the IEA said.

Chinese demand growth is forecast to maintain its global dominance in 2012, at 0.4 mbd to 9.9 mbd or almost half of the total expansion worldwide.

But big declines are foreseen in Europe, down by 0.3 mbd to 13.9 mbd, and the United States, down 0.2 mbd to 18.7 mbd.

Japan, where the economy is recovering from last year's earthquake and tsunami disaster, is expected to buck the OECD trend with demand rising 40,000 barrels per day to 4.5 mbd, buoyed by the country's decision to phase out nuclear energy.

Global oil supply in April increased by 0.6 mbd to 91.0 mbd, the IEA said, with OPEC crude production accounting for more than 70 percent of the increase.

Oil supply from OPEC countries in April rose by 410,000 barrels a day to 31.85 mbd, with Iraq, Nigeria and Libya providing 85 percent of the increase.

The IEA forecast that output from OPEC in the third quarter of 2012 would rise by 0.2 mbd to 30.9 mbd and by 0.4 mbd to 30.7 mbd for the fourth quarter, taking the 2012 OPEC average to 30.3 mbd.

The agency noted that OPEC's April effective spare capacity declined to an estimated 2.38 mbd from 2.54 mbd in March.

The IEA said that higher OPEC output helped offset tighter non-OPEC supplies stemming from unplanned outages.

Non-OPEC supply in March fell by around 600,000 barrels a day amid production disruptions affecting Australia, Colombia, Brazil, the North Sea, the Middle East, and Africa as well as lower US natural gas output.

April output is expected to have improved marginally, and Non-OPEC supplies should grow by around 600,000 to 53.3 mbd in 2012, 90,000 barrels per day lower lower than last month's estimate.

The International Energy Agency is the energy arm of the Organisation for Economic Cooperation and Development, and monitors the oil market, advises OECD-member governments and oversees strategic stockpiles.