In a maneuver to counter the ruling bloc in the coming extraordinary Diet session this fall, Constitutional Democratic Party of Japan leader Yukio Edano and Democratic Party for the People head Yuichiro Tamaki agreed Tuesday to merge their kaiha parliamentary groups in both houses of the Diet.

"I hope that now that we have joined hands, we will be more effective in resisting the high-handed tactics of the current (Prime Minister Shinzo) Abe government in this autumn's extraordinary Diet session," Edano told reporters in Tokyo following the announcement.

"This is the first step in demonstrating to the public that we are an alternative that can stand up to the Liberal Democratic Party," Tamaki told reporters separately.