Bloc Quebecois members are voting on Martine Ouellet's leadership, with the results to be announced Sunday.
Ouellet has said she believes getting the support of 50 per cent plus one will give her the legitimacy to stay on as head of the embattled party.
The Bloc's estimated 14,500 members can vote by telephone or on the internet.
The party has been in disarray since late February when seven of its 10 MPs quit over Ouellet's leadership style.
Of the three who are left, only two still back her.
Ouellet has been described by some as controlling and uncompromising and many of her detractors accuse her of focusing too sharply on Quebec independence instead of defending the province's interests on the federal scene.
In mid-May, the Bloc's youth wing withdrew its support of Ouellet, who is also sitting as an Independent member in the Quebec legislature after stepping away from the Parti Quebecois caucus.
Bloc members will also be voting Friday and Saturday on whether the party should focus on promoting Quebec independence on a daily basis.
