Justin Trudeau said Wednesday that a Liberal government would not get involved in legal challenges to Quebec's religious symbols law, at least not "for the moment."

But that wasn't good enough for the province's premier, François Legault, who wants a commitment from all federal leaders to keep out of the matter "forever."

The polarizing nature of the law — which bars public school teachers and other authority figures in the public service from wearing religious symbols at work — has meant federal leaders have tread carefully around the issue in recent months.

But the topic came up almost as soon as the federal election campaign officially began on Wednesday morning.

Speaking outside the Governor General's residence, Trudeau said he was "deeply opposed" to the law, which is also known as Bill 21.

The law is currently being challenged in Quebec Superior Court by two civil rights groups. Critics of Bill 21 have called on the federal government to seek intervenor status in the case.

Liberal Leader Justin Trudeau talks to media at Rideau Hall in Ottawa on Wednesday. He says he is 'very pleased that Quebecers themselves have chosen to contest' the secularism law. (Justin Tang/The Canadian Press)

But Trudeau said he would leave the matter at the provincial level, for the time being.

"I don't think that in a free society we should be legitimizing or allowing discrimination against anyone," he said. "I'm very pleased that Quebecers themselves have chosen to contest this bill in court, to stand up and defend the Charter of Rights and Freedoms.

"We have been — I have been — watching very closely the process and considering the federal potential actions. For the moment, I think it would be counterproductive for the federal government to engage in this process."

Legault replies

Later Wednesday, Quebec Premier François Legault made his own position clear to reporters.

Though he said he wanted to avoid responding to the statements of individual leaders, he made clear reference to Trudeau's "for the moment" remark.

"I'm asking all federal parties to make sure, and to assure the population of Quebec, that they won't participate in any lawsuit against Bill 21," Legault told reporters at the National Assembly in Quebec City.

"I want them to stay out of it forever — not only for the moment, but forever."

Legault said the law is about Quebecers and has broad support.

"Our government, plus the Parti Québécois, we represent more than 50 per cent of the population," Legault said, referring to the PQ's support for the law.

Conservative Leader Andrew Scheer responds to questions in Ottawa on Wednesday. His says his party has 'no intention of intervening in the judicial process" around Quebec's secularism law. (Paul Chiasson/The Canadian Press)

"We can see right now that the vast majority of Quebecers are for Bill 21, so I think it's not a matter for the federal government."

Bloc Québécois Leader Yves-François Blanchet did not hesitate to defend the law and to emphasize his party's support for it. The law, he said, "is in our comfort zone."

Asked about his position on the issue, Conservative Party Leader Andrew Scheer said he did not want to interfere in Quebec's affairs, although he said he disagreed with the law.

"We have no intention of intervening in the judicial process," he said. "Quebec's elected officials made a clear decision."