TOKYO, JAPAN (AFP) - Toyota Motor Corp. unveiled Tuesday a new hybrid luxury sedan, the "Sai", aiming to keep its pole position in environmentally friendly vehicles.

The new vehicle, which will go on sale only in Japan from December 7, is a compact sedan with a 2.4-litre engine and fuel economy of 23 kilometres per litre, against 38 kpl for the third-generation Prius.

It is the second Toyota-brand vehicle that is available only as a hybrid, after the Prius.

"If it does not carry a hybrid engine, a sedan of this size would require twice as much fuel," said Shigeru Nakagawa, Toyota's project manager.

"When people driving a luxury car want to be more environmentally friendly, they may want a slightly more upscale vehicle than the Prius," he told reporters.

The Sai will have a price tag starting from 3.38 million yen (S$51,714), against 2.05 million yen for the Prius, the company said.

Toyota aims to sell some 3,000 Sai vehicles a month. It sold 31,758 Prius vehicles in September, helped by government tax breaks and subsidies for fuel-efficient vehicles.

The world's largest automaker is a pioneer in hybrids, which run on a combination of petrol and electricity and are in strong demand because of worries about global warming.

Toyota said last month that global sales of its hybrid vehicles had topped the two-million mark since their launch in 1997. It also sells a Lexus sedan that is available only as a hybrid.