NDP leadership candidates Thomas Mulcair, Paul Dewar, Peggy Nash and Nathan Cullen emerged as the perceived front-runners during the party's latest debate Sunday, with the majority of questions pointed at them and not Brian Topp.

Mulcair found himself in the hot seat at the debate in Montreal, as four of his six rivals pointed their first round of questions at the Quebec MP.

Manitoba MP Niki Ashton challenged Mulcair, as she did in previous debates, about comments the veteran politician made about modernizing the party if the NDP were ever to form government.

Mulcair said to Nash there was nothing wrong with "the NDP reaching out beyond our traditional base."

Dewar was the main target of the second round of questions, with Ashton challenging the Ottawa MP about running for leadership while lacking a grasp of the French language.

"It is crucial that the leader of the NDP be bilingual, and I am working very hard to improve my French." replied Dewar.

Topp took few questions compared to previous debates, but leadership rival Martin Singh did not pass up on an opportunity to ask the veteran strategist to explain the impact his tax policies would have on charities.

Topp joked that it would not be a debate without that question from Singh, but when the unelected pharmacist from Nova Scotia accused him of lying, Topp said he found Singh's tone "somewhat harsh for a debate between colleagues."

NDP federal leadership candidates Nathan Cullen, left, Brian Topp and Paul Dewar bump elbows following the conclusion of a leadership debate in Halifax in January. (Tim Krochak/Canadian Press)

The NDP saw a big breakthrough in Quebec during last year's federal election, propelling it to Official Opposition status for the first time. Fifty-nine of its 64 new seats were won in the province, as voters there deserted the Bloc Québécois.

New Democrats started getting their voting packages last week and are already eligible to mail in their ballots or vote online.

Ian Capstick, a long-time New Democrat and strategist, says many in Quebec would have been watching the debate.

"If your French skills are lagging, then you have to prove that you can soar. This is the moment that if you're well established in Quebec you don't falter," said Capstick.

By many accounts, Mulcair has pulled into the lead in this race, but not by enough to win it on a first ballot, which means that those who round out the top four — Dewar, Nash and Topp — could come up the middle.

Mulcair leads fundraising

When it comes to fundraising, Mulcair is leading the way with just over $205,000, compared to $182,000 for Topp, $144,000 for Dewar and $139,000 for Nash.

Cullen has raised almost $130,000, while Singh has raised $57,000 and Ashton $29,000.

Various camps say they've actually raked in more money, but donations from the last couple of weeks are still being processed by the party and have not yet been reported to Elections Canada.

The topic of Sunday's debate was "Moving Canada Forward - Building A Strong, United Canada." The debate was conducted almost entirely in French and moderated by former Action Démocratique Quebec leader Mario Dumont, who now hosts a current events television program.

The seven candidates vying for the leadership of the NDP are Niki Ashton, Nathan Cullen, Paul Dewar, Thomas Mulcair, Peggy Nash, Martin Singh and Brian Topp.

The final leadership debate will take place March 10 in Vancouver.

The new leader, who will replace the late Jack Layton, will be announced at the NDP leadership convention in Toronto on March 24.

Layton died of cancer last August, after leading the NDP to a historic electoral achievement with 103 seats in the May election — which also gave Stephen Harper's Conservatives a majority mandate.