TOKYO (Kyodo) -- Japan's two largest opposition parties said Tuesday they will form a joint group in both houses of parliament in an attempt to challenge the ruling bloc's dominance.
Constitutional Democratic Party of Japan leader Yukio Edano and Yuichiro Tamaki, who heads the Democratic Party for the People, agreed on the plan during a meeting roughly one month after an upper house election that saw the ruling bloc secure a solid win.
After intraparty procedures are complete, the two parties will step up cooperation from an extraordinary Diet session this fall.
"We are making the first step toward becoming an alternative to the LDP," Tamaki told reporters after the meeting, referring to Prime Minister Shinzo Abe's Liberal Democratic Party.
In Japan, it is customary for each political party to have a parliamentary group in each house of parliament.
The opposition leaders had held a series of talks to work out a plan since early August when Tamaki expressed his hope of forming a joint parliamentary group to prepare for the next lower house election.
Despite the envisaged formation of a unified parliamentary group in the House of Representatives and the House of Councillors, uncertainty remains over how much the two opposition parties can coordinate their policies.
The CDPJ and the Democratic Party for the People, together with smaller opposition parties, also joined hands in the July 21 upper house race.
They fielded unified candidates in the nation's single-seat constituencies to avoid splitting the anti-LDP vote, but Abe criticized them for coming together only for the election and putting policy differences aside.
Abe is now calling on opposition parties to step up parliamentary debate on the country's first-ever constitutional reform as his party and other like-minded lawmakers lost the two-thirds majority in the upper house needed to initiate any revision.