Japanese lawmakers have elected Naoto Kan as the country's new prime minister, two days after the surprise resignation of Yukio Hatoyama.

Mr Kan, the outgoing finance minister, promised a "new start" after ruling Democratic Party (DPJ) members chose him as their new leader.

He becomes Japan's fifth prime minister in three years.

Mr Hatoyama resigned as prime minister on Wednesday in a dispute over a US military base in southern Japan.

He had promised to move the airbase off Okinawa island, but failed to find an acceptable compromise to please locals and the US.

In a speech to DPJ members on Friday, Mr Kan said the alliance with the US would remain the "cornerstone" of Japan's diplomacy, but he made no pledges about the base.

"Prime Minister Hatoyama opened the door for a new DPJ to be built," Mr Kan was quoted as saying by the Yomiuri Shimbun newspaper.

"We have to rebuild the party and make a brand new start."

'Straight-talker'

Mr Kan was confirmed as prime minister by votes in both houses of parliament.

The 63-year-old took over the finance ministry in January and has also been serving as deputy prime minister.

He defeated little-known Shinji Tarutoko, chairman of the lower house environmental committee, by a vote of 291-129 among DPJ members of parliament.

Mr Hatoyama's cabinet formally resigned earlier on Friday, clearing the way for a party vote.

Mr Kan is expected to form a cabinet in the next few days, and to be sworn in by Emperor Akihito next week.

The DPJ has been swift to elect a new leader in preparation for upper house elections in July.

The BBC's Roland Buerk in Tokyo says Mr Kan is seen as a straight-talker with a reputation for standing up to the powerful bureaucracy.

He has pushed for higher taxes and spending cuts to tackle Japan's national debt, the biggest in the industrial world.

He is one of the DPJ's most high-profile politicians because of his role in exposing a scandal involving HIV-tainted blood products in the 1990s.

Our correspondent says the new prime minister will have to move quickly to impress voters and to reinvigorate a centre-left government, which many believe has lost its way after just nine months.