Toyota Motor Corp. has unveiled a more expensive and bigger hybrid-only model than its hit Prius, underlining the Japanese automaker's ambitions to make green technology more widespread.

The "Sai" sedan is Toyota's second hybrid-only model after the Prius. Toyota offers hybrid versions of other car models.

Sai, which means "talent" and "color," will be sold only in Japan, starting Dec.7, targeting monthly sales of 3,000 vehicles. No global sales plans have been decided, the world's biggest automaker said Tuesday.

Hybrids get better mileage than regular gasoline engine cars by switching between an electric motor and a gas engine. Other automakers are also beefing up their hybrid lineups, including hybrid-only models.

Government incentives, including cash-for-clunkers programs, and tax breaks are sending Prius orders soaring in Japan, with the waiting list for the car growing to several months.

Hybrid sales in Japan have been the one bright spot for Toyota, which has been losing money, battered by the global economic slump.

The Sai gets 23 kilometers per liter, or about 54 miles per gallon, double the mileage of a comparable regular gas-engine model, according to Toyota.

The Prius gets 38 kilometers per liter, which converts to about 90 miles per gallon under Japanese mileage-test conditions. It is promising 51 mpg in the city and 48 mpg on the highway in the U.S.

The Sai comes with a bigger 2.4 liter engine compared to the 1.8-liter Prius, is roomier and has fancier features such as an interior made from plastic that uses plant-derived materials.

It is also more expensive, starting at 3.38 million yen ($37,500). The third-generation Prius, which went on sale earlier this year, starts at just over 2 million yen ($22,000) in Japan and about $22,000 in the U.S.

The Sai looks rather sedate compared to the Prius with its more circular styling.

"This model shows our hopes to make hybrids more widespread," Toyota official Takuji Nakamoto told reporters.

The Sai will be sold at all dealer outlets in Japan, totaling some 4,000 nationwide, like the Prius. Some Toyota models are sold at just some of the showrooms because they are designed to appeal to certain kinds of consumers.

The Sai will be assembled at a Toyota Motor Kyushu plant in southwestern Japan, Toyota said.

The Prius is the world leader in gas-electric hybrid sales, selling more than 1.4 million vehicles since its debut a decade ago.