A French-language leaders’ debate quickly became heated when the party leaders sparred over the issue of wearing niqabs during citizenship ceremonies.

The issue has become a lightning rod in the election, particularly in Quebec, where a proposed ban on niqabs is popular.

Both Conservative Leader Stephen Harper and Bloc Quebecois Leader Gilles Duceppe are in favour of a ban prohibiting women from wearing the niqab during citizenship ceremonies.

During a heated exchange with NDP Leader Tom Mulcair, Harper said when you join the “Canadian family” citizens do not cover their faces.

“Never will I say to my daughter that a woman has to cover her face because she is a woman,” Harper said in French.

Mulcair struck back, saying if Harper thinks women are being oppressed, then he should “strike” against their oppressors.

“It’s not by depriving these women of their citizenship and their right that you’re going to help them,” Mulcair said, adding Harper was playing a “dangerous game.”

On Wednesday, NDP officials said Mulcair agrees with current rules that require women to remove their face coverings at the ceremonies for identification purposes, but they should not be required to unveil during the swearing in process.

During a campaign event, Mulcair said if elected prime minister, he would withdraw the government’s appeal to the Supreme Court on the face covering ban.

During Thursday's debate, Duceppe said an overwhelming majority of Quebecers support such a ban, and he vowed to extend it to all government services.

“We’re not dividing, I think we’re respecting that basic will that Quebecers have that says men and women should be equal in society and we proposed a bill as early as 2007 requiring that no vote should occur with a covered face,” Duceppe said in French.

Liberal Leader Justin Trudeau accused Harper and Duceppe of wanting to “play on fears and divisive issues.”

But, he also said the Liberals' position on the matter is “quite clear.”

“I believe that if a man cannot impose his will on how a woman dresses, we should not have a state that imposes how a woman shouldn't dress,” Trudeau said in French.

Green Leader Elizabeth May also accused the other party leaders of using the issue of the niqab to distract from real issues in the election.

“We have real challenges in Canada,” May said in French.