Kan, in office just three months, defeated party heavyweight Ichiro Ozawa by an unexpectedly wide margin, 721-491. Media speculation beforehand was that the vote would be much closer.

Kan and his Cabinet should be able to focus on tackling a host of problems confronting Japan, from economic malaise and a surging yen — which on September 14 hit a new 15-year high against the dollar — to an escalating spat with China over a collision near disputed islands.

After the vote, Kan appealed to fellow party members to work together to tackle Japan's challenges.

"Japan is currently in serious difficulty. We must rebuild Japan to make a healthy Japan again in order to hand it to the next generation, and I will stake my life to do the job and gain support from the people," he said.

AP