Japan's Prime Minister Shinzo Abe has dissolved the lower house of the Parliament ahead of a snap election, BBC reported.

The poll, announced on Monday, and which comes a year early, will take place on 22 October.

Abe is seeking a fresh mandate amid a rebound in his approval ratings and the ongoing North Korea nuclear crisis.

The right-wing hawk became prime minister in 2012, and his Liberal Democrat Party (LDP) leads a ruling coalition that controls the Diet.

Abe suffered a drop in popularity earlier this year over allegations of cronyism.

But he's seen fresh support after North Korea fired two ballistic missiles over Japan, which Mr Abe took a strong stance against.

His call for a snap election was seen as taking advantage of a weak opposition, and the LDP is still leading in opinion polls.

But he now faces a new contender in the form of the fledgling conservative Party of Hope, which was only formally unveiled on Wednesday and has already begun attracting some support.

It is led by the popular Yuriko Koike, Tokyo’s first female governor and a former television news anchor.

Several lawmakers from the main opposition Democratic Party, which has been struggling, have already defected to the Party of Hope.

On Thursday, the Democratic Party's leader proposed to his members a de facto merger where all their candidates would run under the Party of Hope's banner, in order to present a united challenge to Mr Abe and the LDP.