Stephen Harper is "playing a very divisive game" with his government's effort to impose a ban on niqabs during the citizenship oath, NDP Leader Tom Mulcair said Monday, just days before a French-language debate in Quebec — a province in which identity politics continues to drive a wedge between voters.

"I'm not about the politics of fear and division. Mr. Harper is going to always go after that. If he senses that there's something there that can divide Canadians one against the other, he'll do it," said Mulcair during a morning campaign stop in Nova Scotia.

The comments came after a reporter asked how Mulcair felt about Muslim women who want to wear a niqab or another type of face covering while taking the oath of citizenship.

"Well, the courts take care of that ... They're there to defend your rights, including freedom of religion," Mulcair said in response, adding that "the courts have spoken in this case."

Last week, an appeals court upheld a lower court's previous decision to strike down a ban on wearing niqabs at citizenship ceremonies. The federal government has since said it will seek a stay on the court's decision until it can take the issue to the Supreme Court of Canada.

Despite the ruling, the wearing of veils at citizenship ceremonies continues to be an issue on the campaign trail, posing a dilemma for Mulcair in his home province of Quebec, where polls suggest a considerable number of voters tend to agree with the Tories.

Conservative Leader Stephen Harper has repeatedly said that the "overwhelming majority" of Canadians, as well as "moderate Muslims," subscribe to his party's position.

The Bloc's wedge issue

The Bloc Québécois has also taken up the issue, saying it would go even further than the Tories and impose a ban on face coverings during citizenship ceremonies and in the voting booth.

Skip Scribble NDP's opposition to a ban on face coverings. A Muslim women's group, however, said the ad "drives a wedge" between Muslims and other Quebecers and insinuates that Muslim citizens are foreigners in the country. It is currently running a deeply controversial ad that the party says is meant to criticize theopposition to a ban on face coverings. A Muslim women's group, however, said the ad "drives a wedge" between Muslims and other Quebecers and insinuates that Muslim citizens are foreigners in the country.

The Bloc is pushing to win back votes it lost to the NDP during the "orange wave" that swept Quebec in the 2011 election. The clash over face coverings is therefore likely to play a central role in Thursday night's French debate in Montreal, where Bloc Leader Gilles Duceppe is expected to draw attention to the fact that there appears to be division within the NDP ranks on the issue.

For example, Quebec NDP candidate Jean-François Delisle said in an interview last week that his party would be amenable to reopening the Constitution to resolve the issue. But the next day he walked back his comments, saying they were "ill-considered and contradictory and do not reflect my priorities or those of the party."

'That's a code word'

For his part, Mulcair has had to negotiate a tricky path on the issue. His party needs to retain the hard-won votes it secured in Quebec in 2011, but cannot risk losing support in the diverse suburbs of Toronto and Vancouver, where voters appear to be opposed to the government's effort to impose a ban.

Part of his approach has been to accuse Harper of dog-whistle politics.

"He talks about 'old stock Canadians,'" Mulcair said this morning, alluding to a comment Harper made during last week's leaders' debate in Calgary.

"That's a code word. He knows what he's doing when he does that."

Liberal Leader Justin Trudeau said earlier this week that the Grits have "always been crystal clear" about their opposition to a ban on niqabs and other veils.

"In any situation where a government chooses to limit or restrict individual's rights or freedoms, it has to clearly explain why. This government has not done that. It is continuing with the politics of division and even fear, and that is not worthy of a country as diverse and extraordinary as Canada."

Thursday's debate is set for 8 p.m. ET.