The Conservative government poses a real threat to liberty in Canada and is stoking fear and prejudice by opposing the right of female Canadian Muslims to wear a niqab, Justin Trudeau says.

And Canadians, he said, should "shudder" that the government is employing the same kind of rhetoric to raise fears against Muslims that was used to promote a “none is too many” restrictive immigration policy toward Jews in the 1930s and 1940s.

"These are troubling times. Across Canada, and especially in my home province, Canadians are being encouraged by their government to be fearful of one another," the Liberal leader said in a speech in downtown Toronto Monday night.

"For me, this is both unconscionable and a real threat to Canadian liberty. For me, it is basic truth that prime ministers of liberal democracies ought not to be in the business of telling women what they can and cannot wear on their head during public ceremonies."

Trudeau, whose speech focused on the theme of liberty in Canada, was referring to the issue of Muslim women wearing the niqab, which covers their face, while taking the oath of citizenship.

Last month, a Federal Court judge ruled that the ban on people wearing face coverings while taking the oath of citizenship is unlawful.

But Prime Minister Stephen Harper denounced that decision, saying that most Canadians would consider it offensive that someone would conceal their identity at the moment they are becoming a citizen.

Harper said the government will appeal that ruling.

In his speech Monday night, Trudeau countered that people should be free to dislike the niqab, hold it up as a symbol of oppression, or convince others they shouldn’t wear one. But those who would use the state’s power to restrict women’s religious freedom and freedom of expression, he said, "indulge in the same repressive impulse that they profess to condemn."

"It is a cruel joke to claim you are liberating people from oppression by dictating in law what they can and cannot wear."

"What’s even worse than what they’re saying is what they really mean. We all know what is going on here. It is nothing less than an attempt to play on people’s fears and foster prejudice, directly toward the Muslim faith."

Trudeau also accused the government of deliberately blurring the line between real security threats and simple prejudice.

In response to Trudeau's speech, Harper spokesman Stephen Lecce said that Canada is a "beacon of freedom, an example of unity in diversity and successful model of pluralism in the world."

Regarding the niqab, Lecce repeated what Harper has said in the past, that Canadians would find it "offensive" that someone would conceal their identity while taking the citizenship oath, which is why the government is appealing the judge's decision.