The election on 22 October is a real hope for Ms Koike, a former LDP defence minister, her newly formed Kibo no To (Party of Hope) would be free of special interests. "We must make North Korea abandon all nuclear and ballistic missile programs in a complete, verifiable, and irreversible manner", he said.
Support ratings for Abe's government have begun to rebound as attacks on its cronyism scandals have faded during parliament's recess, while opposition parties are regrouping.
Mineyuki Fukuda, state minister of the Cabinet Office, said Sunday that he will quit the ruling Liberal Democratic Party to join a party to be created by an aide to Tokyo Gov. Yuriko Koike.
Koike, a media-savvy former TV announcer who defied the LDP to run for governor a year ago, has said she's focused on her current job, including preparing for the 2020 Tokyo Olympics, although she has not ruled out returning to parliament.
He said the world has tried exhaustively to reach a settlement with North Korea, starting with the US-backed 1994 Agreed Framework, which collapsed a decade later.
Abe also said that he would endeavor to better balance Japan's choppy budget book, as rising welfare costs among others, have caused Japan's national debt to continue to balloon, while private consumption remains sluggish owing to lackluster domestic demand and stagnant wages.
If he wins another term, it would put Mr Abe on track to becoming the country's longest-serving political leader in Japan's post-war history. "The decision to hold an election - the very source of democracy - should never be affected by North Korea".
However, a further 42.2% of voters surveyed said they were undecided - which adds a degree of uncertainty to the outcome, with one analyst not ruling out a "nasty surprise" for Abe's ruling party.
The same survey by Nikkei business daily showed 44 percent of voters planned to vote for the LDP.
Abe's support is likely to be buoyed by the economy, which has grown for six straight quarters.
"We need a real force for reform", Koike told reporters in Tokyo.
Abe set the breakup of the powerful lower house of parliament for Thursday because that's when lawmakers return from a three-month summer recess. A total of 475 seats in the lower house will be up for grabs.