Toyota Motor Corp, the world's biggest auto maker, plans to build a new car plant in Japan to revamp its production facilities, domestic media reported on Friday.

The plant would cost up to 80 billion yen ($695 million), have an initial annual production capacity of 100,000 vehicles and come on line in 2010, the Nikkei business daily said.

A separate report by the Nikkan Kogyo newspaper said Toyota would invest about 100 billion yen ($870 million). The plant would have a capacity of 150,000 to 200,000 units and start operations in 2009.

It would be Toyota's first new domestic assembly plant since 1992.

Toyota spokeswoman Shiori Hashimoto said the automaker was always looking to improve its production capabilities but that it had no specific plan to build another assembly factory on its home turf.

Toyota sold a record 8.8 million vehicles last year, overtaking General Motors Corp which had held the title of world's largest auto maker for the previous 75 years.

The Japanese giant is cranking up its share of sales in mature markets in North America, Europe and at home with fuel-efficient models such as the Prius hybrid and RAV4 crossover, and is rapidly expanding in markets such as China and Russia.

This year it expects group sales of 9.3 million vehicles and aims to top the 10 million mark in 2009.

The Nikkei said, however, the new plant was being built to replace an older factory that would close and that Toyota's overall production capacity would not increase.

The Nikkan Kogyo said the new plant would allow Toyota to idle assembly lines at existing plants so that they could be upgraded.

The plant is likely to be located in northern Japan, the papers said.

The Nikkei has also reported that Toyota's main auto parts maker, Denso Corp, will build a plant on the northern island of Hokkaido and that truck maker Isuzu Motors Ltd will build a diesel engine plant there to supply Toyota.

Toyota currently has six assembly plants in Japan and 40 overseas.

Its shares ended up 2.4 percent at 6,530 yen, in line with the auto subindex.