Nagoya Mayor Takashi Kawamura's political group Genzei Nippon (Tax Reduction Japan) became a national political party Wednesday.

The party, trying to promote itself ahead of the next Lower House election, which must be held by summer 2013, was able to register on a national level with the government after finally meeting the requirement of having at least five Diet members, including Koki Kobayashi, who will be its head as Kawamura's proxy.

Kawamura, a former lawmaker of the Democratic Party of Japan, aims for the party to field as many candidates as possible in the next House of Representatives election. Its key goals are to oppose tax hikes, phase out nuclear power and halve Diet members' annual salaries.

Kawamura said he is seeking to create "a third and big political force" that can take on Prime Minister Yoshihiko Noda's DPJ and the Liberal Democratic Party, the main opposition party, in the next election by working closely with other small parties, including one to be formed by Tokyo Gov. Shintaro Ishihara.

Genzei Nippon was able to be established as a national-level party after Atsushi Kumada and Tomohiko Mizuno, both Lower House members, left the DPJ on Monday and signed up, boosting its Diet members to the required five. Genzei Nippon will retain its name and move its headquarters to Tokyo.