The six federal party leaders returned to the stage Thursday for the final debate of the campaign that saw the federalist leaders direct their ire at surging Bloc Québécois Leader Yves-François Blanchet.

Liberal Leader Justin Trudeau and Conservative Leader Andrew Scheer urged Quebecers to reject Blanchet's advances and vote for a party that can form a government after Oct. 21.

Blanchet has improved his party's fortunes in the province after a well-received performance at the last French-language debate.

His better polling numbers have come at the expense of Scheer, who started the campaign with a plan to pick up more seats in Quebec to help secure a majority Tory government and make Trudeau a one-term prime minister. That plan seems to have faltered after a shaky showing by Scheer in the TVA debate. Trudeau has also seen an erosion in Liberal numbers in the province. A strong result in Quebec is also central to the Liberal Party's re-election plans.

Trudeau and Scheer have been in a battle for front-runner status since the launch of this campaign last month. The CBC News's Poll Tracker has the two locked in a statistical dead-heat for first, with both clocking in at roughly 33 per cent countrywide.

Singh, who was widely declared the winner of the last English debate, has seen an improved showing in national polls, although his numbers in Quebec remain low. In an effort to reverse that, he made a direct appeal to Quebecers Thursday saying he is a "francophile" who shares the values of Quebecers on abortion and women's rights.

Trudeau, Scheer take on Blanchet

Liberal Leader Justin Trudeau said his party is counting on Quebecers to return more Liberal MPs to Parliament on Oct. 21 so his government can continue the fight against climate change.

He said only the Liberal Party is well-positioned to take on Conservative premiers like Jason Kenney and Doug Ford, people he said who are beholden to "oil barons" determined to push through natural resources projects at any cost.

He said a vote for Blanchet would be akin to a vote for Scheer because opposition Bloc MPs will never be part of a pan-Canadian government with a mission to tackle the pressing environmental issues of our time.

"We need to keep going. We can't stop. It's important Quebecers, francophones and all Canadians be part of a government that wants to fight climate change," he said.

Liberal Leader Justin Trudeau says Bloc Québécois Leader Yves-François Blanchet can't fight climate change because he will never form government and implement a pan-Canadian climate change plan. 0:56

Trudeau said voting Bloc would simply bring more "Harperites" back to Ottawa, a reference to the former Conservative government led by Stephen Harper.

"A strong Bloc Québécois in Ottawa could not prevent Mr. Harper from doing nothing on the environment ... from cutting on culture. We need a strong federal government with great Quebecers part of it," Trudeau said.

Liberal Leader Justin Trudeau says Quebecers need to think twice about voting for the Bloc Québécois because it would bring back a government like the one led by former prime minister Stephen Harper. 0:39

Scheer said Blanchet likes to present himself as a "best friend" of Quebec Premier Francois Legault, the popular nationalist leader who has opposed efforts to re-open the separatism debate and yet Blanchet is a former member of a party that is determined to break up the country.

Scheer said electing Blanchet, a former member of a Parti Québécois (PQ) government, would revive old sovereignty debates at the expense of national unity.

"What is clear is that Mr. Blanchet's priority is to try and stir up sovereignty once again. He will work with the PQ to lead to a referendum — that's his priority and that's clear," Scheer said.

Conservative Leader Andrew Scheer says voting for the Bloc Québécois will do nothing for Quebecers because it will simply return another Liberal government to Ottawa. 2:03

Blanchet said Scheer's attacks were "bizarre."

"Oct. 21 is not the day of a referendum, it's a federal election," he said.

Scheer said electing more Bloc MPs, who, by their very nature will forever be confined to the opposition benches, would deny the Conservative party the chance to form government.

Scheer's Conservatives compete with the Bloc in the more rural areas of the province and in mid-size cities like Saguenay. Trudeau's Liberals compete against the Bloc for seats in off-island Montreal suburbs like Longueuil.

Scheer accuses Trudeau of lying

Scheer continued his direct attacks on Trudeau on Thursday, calling him a "liar" on matters like the SNC-Lavalin scandal, but also on how he's characterized the Conservative tax cut plan.

Trudeau accused Scheer of wanting to hand tax cuts to "millionaires," by reversing some of the Liberal changes to the small business tax regime that closed some "loopholes" that allowed for income sprinkling among family members.

"You are lying," Scheer said on the charge that millionaires stand to gain thousands under the Conservative plan.

PPC Leader Maxime Bernier says the country's credit card is full. Liberal Leader Justin Trudeau says both Bernier and Conservative Leader Andrew Scheer are floating arguments of ex-PM Stephen Harper, as Scheer accuses Trudeau of lying. 2:19

"Justin Trudeau continues the lie that the Globe and Mail story was false," Scheer said of the first media report about inappropriate pressure on former justice minister Jody Wilson-Raybould on the SNC-Lavalin matter.

Trudeau defended his actions on the file, saying he was concerned that the bad actions of corporate leaders could result in job losses for workers. He said other countries, including European partners, have deferred prosecution agreement (DPA) regimes in place, the legal mechanism some in government suggested Wilson-Raybould should apply to the Quebec engineering giant.

Conservative Leader Andrew Scheer says world leaders 'simply don't respect' Liberal Leader Trudeau after his "disastrous" trip to India, at the final federal leaders debate. 1:04

Scheer also said Trudeau has been an embarrassment on the world stage saying, after the Liberal leader's "disastrous" trip to India, leaders simply don't respect him any more.

Singh also launched an attack on Trudeau during the debate Thursday, saying he hasn't show the sensitivity required to help the people of Grassy Narrows, a northwestern Ontario First Nations reserve that is grappling with the effects of mercury poisoning.

At a fundraising event this spring interrupted by protesters from the reserve, Trudeau jokingly thanked them for their donation.

NDP Leader Jagmeet Singh scolds Liberal Leader Justin Trudeau for his "incomprehensible" comments to Grassy Narrows activists at a fundraising event. Trudeau promises to fund a treatment centre to deal with mercury poisoning. 1:09

"You made fun of someone who's an advocate. It's incomprehensible how some could do that. If you had visited that community and saw the intoxication, the poisoning, it's incredible," Singh said.

Trudeau said his government has promised to make the funds available for a treatment centre. "We will make sure the funding is in place," Trudeau promised.

Singh says he's a 'francophile'

NDP Leader Jagmeet Singh said he understands he looks different from many Quebecers, given he wears a turban, but he assured voters in the province that he shares their values on things like abortion, same-sex marriage and the equality of sexes.

"I'm not a francophone but I'm a francophile. I fell in love with the French language. It has been a source of wealth in my life," Singh said. "Yes, I wear a turban but we share the same values."

Trudeau, meanwhile, presented himself as the strongest defender of francophone rights, saying he has tried to reverse Ontario's cuts to minority language institutions through "record" investments.

In a direct appeal to Franco-Ontarians, Trudeau said: "We understand the fight that you're fighting every day and we'll be alongside you."

NDP Leader Jagmeet Singh says he's a "francophile" and will improve services in French outside Quebec. Blanchet says francophones should be served just as well as anglophones are in Quebec. Liberal Leader Justin Trudeau says he's an ally of Franco-Ontarians in the face of Doug Ford's cuts. 1:40

Singh said he'd respect provincial jurisdiction and not intervene in a court challenge to the province's controversial secularism law, Bill 21, the legislation that forbids public servants from wearing religious symbols on the job.

May calls for an end to 'squabbling' on Bill 21

Green Party Leader Elizabeth May showed frustration at the end of the two-hour debate, saying too much time in this campaign has been spent debating Bill 21 and whether or not a party led by a particular leader would intervene in a court case.

May said she wished the party leaders would stop "squabbling" on this and focus their energies on dealing with climate change.

NDP Leader Jagmeet Singh says he wears a turban and he shares Quebec values. And he says he doesn't want to intervene in a court case to overturn the province's secularism law, Bill 21. 0:56

The comment came after both Scheer and Singh said they wouldn't intervene and they'd respect the will of Quebec legislators for now.

Blanchet accused Singh of saying something different in the country's two official languages. On Monday, in English, Singh said he'd consider joining a fight against the bill if the legal case makes it to the Supreme Court of Canada. Singh was more definitive Thursday that the NDP would stay on the sidelines.

"We have spent a lot of time on small politics — let's work together to fight the climate emergency," May said. "I think that's an issue for Quebec and Quebecers, but right now, please, we have to talk about what's going to happen in north of Canada, in the Arctic ... climate change."

On the climate change file, People's Party Leader Maxime Bernier took aim at Scheer's plan for the environment, which includes funding technological innovations that can be exported to countries around the world looking to reduce emissions.

Bernier said Scheer is too focused on emissions in other countries to the detriment of Canada.