TOKYO, June 6 (Reuters) - Toyota Motor Corp said on Friday it has developed an advanced fuel-cell vehicle that can run for 830 km (516 miles) on a single tank of hydrogen and in temperatures as low as 30 degrees Celsius below freezing (-22 F).

The zero-emission FCHV-adv will be leased to government agencies, among other possible users, in Japan starting later this year, a spokeswoman said.

The new version of the fuel-cell car, which runs on hydrogen and emits only water, increased fuel efficiency by 25 percent with an improved fuel cell unit and other changes to its brake system and elsewhere.

Combined with a slightly bigger fuel tank and a doubling of the maximum storage pressure, the FCHV-adv extended the cruising range from the previous FCHV's 330 km (205 miles), Toyota said in a statement. It has a maximum speed of 155 km per hour (97 mph).

Fuel-cell vehicles are widely considered the ultimate longer-term alternative to today's conventional cars as they run on an inexhaustible and cheaper source of fuel - hydrogen - have no harmful tail-pipe emissions, and do not compromise driving performance. The main hurdles for their proliferation are a lack of fuelling stations and the high cost of development.

Toyota and domestic rival Honda Motor Co became the world's first two automakers to put a fuel-cell vehicle on the road in December 2002, and have since been in a tight race to prepare them for mass-commercialisation.

Honda's latest FCX Clarity, a sporty-looking fuel-cell sedan, can run 620 km (385 miles) on a single fuelling as measured under Japan's fuel efficiency test method. It can go as fast as 160 km per hour (99 mph), uses a lithium-ion battery and can withstand temperatures from -30 to 95 degrees Celsius (-22F to 203F).

Honda plans to begin leasing the car in the United States starting next month and in Japan later this year. It is targeting lease sales of about 200 FCX Clarity cars in the first three years in the two countries combined.

Toyota's FCHV-adv, which uses a nickel-metal hydride battery, will be showcased as a test-ride vehicle at the Group of Eight rich nations' summit in Toyako, northern Japan, next month. It will also provide more than 70 hybrid cars and hydrogen-fuelled buses for use by summit participants.

Japan's Mitsubishi Motors Corp said separately on Friday it would provide 10 of its i-MiEV pure electric minicars for the summit. The automaker plans to bring the rechargeable electric cars to market in Japan next year, while plans are also underway to begin fleet testing at some U.S. power companies as early as this autumn.

(Reporting by Chang-Ran Kim; Editing by Michael Watson)