Growth in crude oil output by the Organization of Petroleum Exporting Countries will be very slow in 2013, the chief executive of an international energy consulting company said on Thursday.

The cartel may even reduce its crude output next year to some extent to maintain market balance, considering the state of the global economy and the financial market for crude, said Gary Ross, chief executive officer of PIRA Energy Group.

He said crude output will grow next year in non-Opec countries such as Canada and the United States, while "emerging countries", including China and India, will become the driving force for crude oil demand in the world.

"US shale oil production growth and the urbanization of emerging economies are two major factors in the crude oil market," he said.