Popular Tokyo Gov. Yuriko Koike launched a new political party Wednesday, promising to "reset" Japan and restore its international prestige, while also posing a powerful threat to Prime Minister Shinzo Abe as the nation braces for a high-stakes snap election next month.

The populist governor's latest foray into national politics has reportedly also opened the door for a struggling opposition Democratic Party to explore a potential tie-up with her party. The new DP leader, Seiji Maehara, is trying to figure out how best to counter Abe's ruling coalition in the October poll, including mulling a merger with the fringe opposition Liberal Party, according to local media.

By launching the new party, "we are determined to reset Japan and realize politics not beholden to any special interests," Koike told a packed news conference in Tokyo.