Members of two of Quebec's best-known sovereigntist clans are battling it out for a chance to represent the Bloc Quebecois in a Montreal riding in the upcoming federal election.

Anne Duceppe, the cousin of former Bloc leader Gilles Duceppe, is facing the outgoing leader of the Communist Party of Quebec, Andre Parizeau, the nephew of former Quebec premier Jacques Parizeau.

They are seeking to represent the Bloc in north-end Ahuntsic-Cartierville, where a nomination meeting is set for Aug. 17.

The successful candidate will face off against Liberal Melanie Joly, who won the federal riding for the Liberals in 2015 with more than 46 per cent of the vote.

Some within the party, including the former Bloc leader, have raised concerns about Parizeau's recent communist affiliations.

In a July 28 statement, the Communist Party of Quebec, which split from the Communist Party of Canada and is not registered as an official party, confirmed Parizeau was stepping down as leader to "avoid any possible ambiguities."

Parizeau, who already held a position in the Bloc as an adviser, confirmed his candidacy in Ahuntsic-Cartierville on Aug. 1.

Reached by The Canadian Press, Gilles Duceppe expressed concern about Parizeau's recent involvement in the communist party.

"I think that when you are a member of the Bloc, you should be a member of the Bloc only and not another party at the same time," he said.

The former Bloc leader, who in his youth advocated communism and was a member of the Workers' Communist Party of Canada, now says that communism was "a monumental mistake."

"Now we are in a democracy, people can decide to run for a nomination," he said. "It is the members who decide."

Anne Duceppe announced her intention to run on the weekend, prompting Parizeau to write on social media that she was being parachuted into the riding.

He accused her of wanting to run in a different riding in the Quebec's Laurentians region where she lives before changing her mind and seeking the nomination in Ahuntsic-Cartierville.

Neither Anne Duceppe nor Parizeau was immediately available for comment.