Canadian opposition leaders accused Conservative Prime Minister Stephen Harper of playing divisive politics Thursday in a French-language debate ahead of next month's election.

Harper has been promoting a law to ban the practice of Muslim women wearing face veils while swearing the oath of citizenship. The anti-niqab law is popular in Quebec.

Polls say the Oct. 19 election is a three way toss-up. According to the CTV/Globe and Mail/Nanos Nightly Tracking Poll, the Liberals are at 31.5 percent while the leftist New Democrats are at 30.8 percent and the Conservatives at 30.5 percent. The margin of error for the survey of 1,200 respondents is 2.8 percent

Harper lost a court decision to ban the practice of wearing face veils while swearing the oath this month. He's appealing to the Supreme Court.

"Swearing an oath with a covered face does not fit with our values," Harper said.

"Never will I say to my daughter that a woman has to cover her face."

Harper engaged in a heated exchange with New Democrat leader Tom Mulcair, who said Harper is playing a dangerous game of politics and trying to hide his record behind a niqab.

"Tackle the oppressor if you believe that there is oppression there," Mulcair said, adding the prime minister was using the issue as a "weapon of mass distraction."

Liberal leader Justin Trudeau said Harper is playing on fears and said men shouldn't tell women how to dress, nor should government. "I understand it's a question that makes many people uneasy, but for me, the state is there to defend minority rights, and to defend the rights of women," Trudeau said.

The issue of the niqab only touches a tiny fraction of Canada's one million Muslims but Harper has played up the issue to win favor in French-speaking Quebec and with his conservative base.

Since coming to power in 2006, Harper has managed to pull a traditionally center-left country to the right. He has gradually lowered sales and corporate taxes, avoided climate change legislation, supported the oil industry against the environmental lobby and backed Israel's right-wing government.