Toyota Motor Corp. is preparing to divulge details of the hybrid-car engine technology it pioneered with the Prius to China in an attempt to catch up with rivals in the world's biggest auto market.

Chinese officials asked Toyota to share its gasoline-electric technology to help local companies meet stricter emissions targets, people familiar with the matter said, asking not to be named because the talks are private. Seeing this as a chance to make inroads in China, Toyota has engaged in advanced talks to license its hybrid system to Chinese carmaker Geely Automobile Holdings Ltd., two of the people said.

Government backing for hybrid vehicles would be a boon for Toyota's ambitions to boost sales in China. Hybrids have been a success for Toyota in Europe and Japan for years, but China has so far placed more focus on so-called pure electric vehicles, promoting them through subsidies and tax breaks.