TOKYO -- Two Japanese major opposition parties unveiled a plan on Tuesday to merge and form a new party ahead of the upper house election this summer in a move to better challenge the ruling coalition led by Prime Minister Shinzo Abe.

The Democratic Party of Japan (DPJ), the largest opposition party here, and the Japan Innovation Party (JIP) announced their plan to form a new party, and, according to their plan, the new party will be established in late March at earliest, said local reports.

The JIP will be dissolved and then will be merged into the DPJ, which will maintain its factions, but the name of the "Democratic Party of Japan" will be changed, according to the JIP's merge proposal, although veteran DPJ lawmakers insisted keeping the DPJ's name.

DPJ executives approved the integration plan during a meeting on Tuesday and the JIP leader Yorihisa Matsuno also introduced the plan to his party.

The two parties will discuss the issue when they each hold intraparty talks on Wednesday so as to gain support within their parties respectively, according to Japan's Kyodo News.

If merged, the new party will have 93 seats in the 475-seat lower house, where the ruling coalition grouped Abe's Liberal Democratic Party and the Komeito Party secures 325 seat in the all-powerful chamber, and 64 seats in the upper house. The ruling camp also maintained the majority in the 242-seat chamber.

Half of the 242 seats in the upper house will be elected every three years.