The forecast of slower growth in oil demand puts the IEA increasingly in a camp of contrarians bucking the popular view that crude demand will grow briskly in a postrecession world. That view holds that long-term demand will grow at a fast clip because of rising emerging-market wealth and consumption in places like China and India.

The IEA, which advises rich nations, such as the U.S., on energy matters, is set to use its closely watched annual World Energy Outlook report to forecast that improved energy-efficiency measures in developed nations, as well as climate-change legislation, will help to slow the rate of global oil consumption.

A person familiar with the Paris-based IEA's plans said "demand-management policies" are having more impact than previously expected in the developed world, which accounts for about 55% of world oil consumption. The IEA outlook, a guidepost for industry trends, is scheduled to be released Nov. 10.

A drop in industrial activity from the recession is also a big factor in the revision. Baseline assumptions used in the previous long-term outlook have to be adjusted down to account for the tough economic conditions of the past year.