Dependency on oil produced by OPEC countries is set to rise in the next 5-10 years as non-OPEC supplies are set to decline, Nobuo Tanaka, executive director of the International Energy Agency (IEA), said on Friday.

"It (non-opec oil supply) is not really increasing, it is levelling off and then it will decline so dependency on OPEC will increase. Cost of development in OPEC is cheaper," Tanaka told reporters.

He was speaking at the launch of the organisation's Energy Technology Perspectives 2010 report.

The IEA, which advises 28 industrialised countries, said global oil demand would rise by 1.8 million bpd (mbpd) year-on-year to 86.6 mbpd in 2010, which was 80,000 bpd higher than the forecast in its July report.

OPEC crude oil supply fell in August to the lowest since November 2009 as reduced supplies from Nigeria, the United Arab Emirates and Iraq offset increased output in Angola, a Reuters survey showed on Wednesday.