Both Toyota and General Motors are committed to launching a new generation of plug-in hybrid vehicles over the next two years but they are far from being the only carmakers in the race to develop the ultra-efficient vehicles. A Nissan official has today revealed that his company has already starting testing its own plug-in prototypes and is considering greenlighting the project for production.

Speaking with the Associated Press, Nissan spokesman Mitsuru Yonekawa confirmed that the carmaker was considering developing plug-in hybrid vehicles in response to rising fuel prices and the fear of not being a technology-leader but was unwilling to give any further details.

Last month Nissan unveiled the first prototype for its own proprietary hybrid drive system in an Infiniti G35 sedan (pictured). The system, which features two clutches, where the electric motor is directly connected to the engine and transmission via these two separate clutches, is scheduled to enter production in 2010. However, Nissan has a lot of work to do if it intends on catching with market leader Toyota. Its initial test vehicles were found to have a significant number of bugs, and on the first media test drive the cars tended to lurch and vibrate every time the petrol engine powered up or the regenerative brakes kicked in.

Nissan has always looked towards all-electric vehicles as a way to leapfrog its rivals in the technology stakes, but with Toyota announcing this week that it also plans to build an all-electric car and Mitsubishi just months away from real-world testing of its i-MiEV model, the race is now on to be first on all fronts.