OTTAWA -- NDP leadership hopeful Niki Ashton says she is expecting twins in early November, shortly after her party selects a successor to Tom Mulcair.

Ashton says she is looking at a three-month leave window available to her as an MP following the birth of her babies, though she plans to remain engaged in her work should she become the party's new leader.

She has yet to determine whether an interim leader in the House of Commons would need to be named during that period.

Ashton and her fellow candidates -- Ontario MP Charlie Angus, Quebec MP Guy Caron and Ontario legislator Jagmeet Singh -- will participate in a French-language debate this Sunday in Montreal.

The final debate will be held in Vancouver on Sept. 10 but Ashton says she will have to appear by video conference due to flying restrictions that apply at that point during her pregnancy.

Party members will begin casting their ballots online just over a week later on Sept. 18.