Several Lower House members of the Democratic Party are considering quitting over its election cooperation alliance with the Japanese Communist Party, sources familiar with the situation said.

The members are expected to submit their letters of resignation to the major opposition party as early as this week.

“A decision to leave the party needs to be made within this week,” one of them said.

The dissenters are mainly members of an intraparty group once led by former Environment Minister Goshi Hosono, who quit the DP last month.

Defections would represent another setback for new DP President Seiji Maehara, who just lost his first choice for secretary-general, Lower House member Shiori Yamao, after she resigned amid allegations of an extramarital affair last week.

The dissenters think it will be difficult for the DP to revive its fortunes under Maehara’s leadership and skipped a general meeting of the party on Tuesday at which his new executive team was inaugurated.

After exiting, the dissenters are expected to explore the possibility of forming a new party this year with Hosono and independent Lower House member Masaru Wakasa, a close aide to Tokyo Gov. Yuriko Koike.