The move comes at an opportune time for General Motors with the price of oil hovering around the $US33 a barrel mark. It is understood GM's strategy is to offer hybrids in its most popular models, including the notorious gas-guzzling trucks and sport utilities (SUVs), in order to pump up sales volume and quickly amortise development costs.

The company said it did not expect its hybrids, after federal and state tax incentives are applied, to cost much more than traditional vehicles powered by internal combustion engines.

Hybrids use two or more power sources, usually a petrol engine augmented by one or more electric motors. Some, called "mild" hybrids, use the electric motors for auxiliary power and to restart the petrol engines that shut down when the vehicle stops.