Béatrice Zako was set to run for the New Democrats in the Montreal riding of Papineau, which is held by Liberal Leader Justin Trudeau, in the upcoming federal election.
Zako was a member of the national council of the left-wing provincial sovereigntist party Option Nationale for three months in 2013.
She has been quoted as saying she "couldn't wait to exchange her Canadian passport for a Quebec one," and, in an Option National party bio, compared Quebec's struggle for independence to that of African countries under colonial rule.
As of last Thursday, the NDP maintained it was comfortable with Zako's sovereigntist past.
But in a statement obtained by The Canadian Press, Zako admitted she had not revealed all of her past statements to the NDP.
Zako said "her statements are incompatible with the NDP's vision" and she doesn't want to be a distraction for the party.