Japan’s Prime Minister Naoto Kan on Thursday survived a no-confidence vote after pledging to step down once the country is firmly on the road to recovery from the March 11 quake and nuclear disaster.

The promise to hand over power to a younger generation mollified internal party rebels who had threatened to bring down Kan, the country’s fifth Premier in as many years, days before his first anniversary in the job.

The motion, brought by the conservative Liberal Democratic Party (LDP) and two small parties, was defeated by a margin of 152 against 293 after most lawmakers of the centre-left ruling party fell into line behind Kan.

Kan, 64, in a last-minute appeal to his fractured Democratic Party of Japan (DPJ), urged its lawmakers to stick together until his government makes significant progress in rebuilding from Japan's worst post-war emergency.

“Once my handling of the earthquake disaster is settled to some extent and I have fulfilled my role to some extent, I would like younger generations to take over my various responsibilities,” said the Prime Minister.

The self-styled “son-of-a-salaryman”, or man of the people, premier offered no precise milestone, leaving his departure date open to interpretation.

The government has promised that most of the 100,000 people still living in shelters since the March 11 disaster would be in temporary housing by mid-summer, but wider reconstruction efforts are expected to take years.

The operator of the tsunami-hit Fukushima nuclear power plant has said it hopes to bring its six reactors to “cold shutdown” by October-January, but decommissioning and decontaminating the site will take far longer.

The LDP — which was ousted in a landslide 2009 election after more than half a century of almost unbroken rule — submitted the no-confidence motion late on Wednesday with two small parties.

LDP leaders have accused Kan of bungling the response to the disaster that left more than 23,000 dead and missing and sparked the world's worst nuclear crisis since Chernobyl a quarter-century ago.

Kan's archrival within the DPJ, scandal-tainted powerbroker Ichiro Ozawa, abstained from the vote, in which 30 lawmakers loyal to Ozawa also either failed to cast a ballot or voted in support of the Premier.

Another Kan critic within the DPJ, former Premier Yukio Hatoyama, earlier threatened to vote against Kan but in the end backed him, after saying the ruling party and nation should be united at a time of crisis.

Asked after the vote by reporters when he thinks Kan should quit, Hatoyama said the Premier should bow out this summer.

Kan’s ouster would have perpetuated Japan’s much-criticised revolving-door leadership as the world’s number-three economy struggles with flagging growth and a huge public debt mountain.

The Premier had urged DPJ lawmakers in a pre-vote party meeting: “Let me fulfil my responsibilities until we see the (reconstruction) work near settlement. Let me meet this responsibility with all of you.”

After the vote, the LDP secretary general Nobuteru Ishihara, called the result “unfortunate” and complained about Kan’s vague wording, criticising his “very fuzzy and irresponsible remarks”.

“The Prime Minister said he will quit once the work of earthquake reconstruction is finished to ‘some extent’,” Ishihara said.

“But there is no milestone in sight even for the nuclear accident. There is no clear strategy for rebuilding after the earthquake.

“We have been saying the reconstruction effort cannot progress under the leadership of Prime Minister Kan.”