OTTAWA -- Bloc Quebecois Leader Martine Ouellet must regain the confidence of her caucus, seven of the party's 10 MPs said Wednesday.

The party is challenging Ouellet's leadership after a news report revealed her chief of staff, Louis-Philippe Dubois, allegedly leaked information to the press in order to tarnish a Bloc MP's reputation.

"We learned that Louis-Philippe Dubois was working more against Bloc MPs than for the Bloc," House leader Gabriel Ste-Marie told a news conference surrounded by six other caucus members.

"It was an enormous lack of judgment to have named Dubois as chief of staff. We told her (Ouellet) he didn't have the competencies and that he didn't have our confidence."

HuffPost Quebec reported Wednesday that Dubois allegedly tried to sully the reputation of Bloc MP Rheal Fortin by leaking information about him and the law firm where he used to work.

In response to the news story, Ouellet fired Dubois and said he had lost the trust of the caucus.

Ste-Marie said Fortin, who used to be Bloc leader, is a respected member of the party.

"We are with him and he has our full confidence," Ste-Marie said.

The Bloc caucus will meet Thursday morning to discuss the matter.

Tensions have been rising in the Bloc since Ouellet was recently named party leader.

She has not been elected to the Commons and continues to sit as an Independent in Quebec's legislature after a long stint with the Parti Quebecois.