At its convention in Tokyo on Sunday, the New Komeito party, the junior partner in Japan's ruling coalition, approved a fourth two-year term — until September 2016 — for its leader, Natsuo Yamaguchi.

Other party executives, including Secretary-General Yoshihisa Inoue and Kazuo Kitagawa, New Komeito's deputy chief, also retained their posts.

"As part of the ruling coalition, we would like to support the Cabinet and move toward realizing policies," Yamaguchi said during the convention, referring to efforts to rebuild after the 2011 earthquake, tsunami and nuclear disasters, and revive the country's economy.

He also underlined the need to craft a supplementary budget for fiscal 2014 to prevent the planned additional consumption tax hike next year to 10 percent from 8 percent from affecting the economy.

Prime Minister Shinzo Abe, whose Liberal Democratic Party forms the ruling coalition along with New Komeito, said as a guest, his party will try to win the quadrennial unified local elections next spring "together with New Komeito and complete the return to power."

The LDP returned to power in the general election in December 2012 after limited gains in the previous unified local elections in April 2011.