The world's top automaker Toyota Motor plans to launch six new hybrid models by the end of 2012, a spokesman for the company said Tuesday, as competition to build greener cars heats up.

The six planned models will expand Toyota's hybrid-engine range of vehicles that run on gasoline and electricity at a time when rivals such as Nissan are developing all-electric vehicles.

The Wall Street Journal, citing a Toyota official in Detroit, said that the six new hybrids would include two luxury brand Lexus vehicles and four Toyota models.

Some will be hybrid models only -- like the Prius -- while others will also have a gasoline-engine variant, the report said. All of the hybrids will be new, and not next-generation versions of existing models.

Toyota's Prius hybrid has been a success for the carmaker, particularly in Japan where the compact vehicle has topped the country's best-seller list since May 2009.

The automaker has been plagued by safety recalls in the past year for unintended acceleration, engine, steering and brake problems, with around 10 million vehicles in total affected.

It is now looking to compete with rivals in the increasingly competitive environmentally friendly market.

Nissan's all-electric Leaf vehicle, which has a top speed of more than 140 kilometres (90 miles) per hour and is powered by a lithium battery, will go on sale later this year.

The Leaf -- which stands for Leading, Environmentally Friendly, Affordable, Family car -- is billed by Nissan as the world's first mass-produced electric vehicle with zero emissions.

Nissan hopes electric vehicles will boost growth and compete with Mitsubishi Motors' i-MiEV and Fuji Heavy, which makes the Subaru Plug-in Stella.

Toyota will also unveil a fully electric version of its RAV4 sport-utility vehicle, developed with its US partner Tesla, at the Los Angeles auto show in late November, the Tokyo-based spokesman said Tuesday.

Tesla and Toyota announced a partnership in May to develop electric vehicles using technology from the California-based start-up.