He seeks a fresh mandate to overcome “a national crisis."

Japanese Prime Minister Shinzo Abe said he would dissolve Parliament's lower house on Thursday for a snap election, as he seeks a fresh mandate to overcome “a national crisis."

Mr. Abe, in power for five years, said he needed a mandate to shift some revenues from a planned future tax hike to social spending such as education, besides seeking support for a tough stance toward North Korea's repeated missile and nuclear tests.

“I will dissolve the lower house on September 28,” Mr. Abe told a nationally televised news conference on Monday.

Earlier, the head of Mr. Abe's junior coalition partner, Natsuo Yamaguchi, said he understood the election would be held on October 22.

The decision is largely seen as aimed at taking advantage of Mr. Abe's recently improved support ratings and Opposition disarray.

Mr. Abe, whose ratings have risen to around 50% from around 30% in July, is gambling his ruling bloc can keep its lower house majority even if it loses the two-thirds “super majority” needed to achieve his long-held goal of revising the post-war pacifist constitution to clarify the military's role.

Strong leader image bolsters his ratings

Mr. Abe's image as a strong leader has bolstered his ratings amid rising tension over North Korea's nuclear arms and missile programmes and overshadowed Opposition criticism of the Premier for suspected cronyism scandals that had eroded his support.

Some critics say Mr. Abe has risked creating a political vacuum at a time of rising geopolitical tension over North Korea.

And, given the unexpected results seen in other major developed countries, political analysts are not ruling out a "nasty surprise” for the Japanese leader.

Mr. Abe told LDP executives at a meeting that he intended to dissolve the lower house on Thursday. He was expected to face a grilling over the cronyism scandals during Thursday's session, and Opposition party officials saw the move as play to avoid difficult questions.

Sources said Mr. Abe's election platform would see him promise to go ahead with a planned rise in the national sales tax to 10 percent from 8 percent in 2019 but increase the proportion of revenue spent on child care and education, delaying a target of putting the budget in the black in the fiscal year ending March 2021.

Mr. Abe on Monday asked his Cabinet to compile a 2-trillion-yen ($17.8-billion) economic package by year-end to focus on childcare, education and encouraging corporate investment, while maintaining fiscal discipline.

The Yomiuri newspaper said earlier that the funding would cover the three years from April 2018 until sales tax revenue kicks in.

The main Opposition Democratic Party is struggling with single-digit ratings and much depends on whether it can cooperate with liberal Opposition groups.

Tokyo Governor to float new party

On Monday, just hours before Mr. Abe's election announcement, Tokyo Governor Yuriko Koike said she would lead a new conservative, reform-minded “Party of Hope", to offer voters an alternative to the LDP.

“Our ideal is to proceed free of special interests,” Ms. Koike, a former LDP member, told a news conference.

Over the weekend, a junior LDP Cabinet Minister, Mineyuki Fukuda, said he would leave the ruling party to stand for election with Ms. Koike's new group.