The federal NDP is losing another incumbent, as Quebec MP Marjolaine Boutin-Sweet says she will not be seeking re-election later this year.

The decision represents the latest blow to the third-place party, which has already seen a slew of MPs leave or announce their decision not to run for another term in October.

That list includes Alberta MP Linda Duncan, Ontario MPs Irene Mathyssen and David Christopherson, Quebec MPs Tom Mulcair, Helene Laverdiere and Romeo Saganash, and B.C. MPs Kennedy Stewart, Sheila Malcolmson and Fin Donnelly.

Boutin-Sweet was first elected during the so-called Orange Wave in 2011, when the NDP under then-leader Jack Layton rode historic gains in Quebec to become the Official Opposition.

But the NDP has struggled in more recent years, particularly in Quebec, where the party has suffered several poor byelection results and support in the polls has stagnated under current leader Jagmeet Singh.

New Democrats are hoping to turn things around next week in byelections for the Montreal riding of Outremont, which was held by former party leader Mulcair, and the B.C. riding of Burnaby South, where Singh is running.