NDP Leader Thomas Mulcair says he supports any measure that will reduce the threat of terrorism, but questions whether banning Canadians from travelling to regions controlled by terrorist groups would “make a big difference, practically speaking.â€

Mulcair made the remarks after Conservative Leader Stephen Harper said Sunday that he would follow the lead of Australia and make it illegal to travel to “declared areas†in foreign countries where terrorist entities such as ISIS are fighting and training.

Harper said during a campaign stop in Ottawa that "there is absolutely no right in this country to travel to an area under the governance of terrorists†and that “we're not under any illusion here what just about everybody going to an area like that is doing.â€

Harper said there may be "certain, rare circumstances†where Canadians have legitimate reasons to travel to such places under such legislation and that “there will be exceptions in the law for those.â€

The Conservatives have not said which regions would be declared no-go zones for Canadians, but Australia’s foreign minister has declared ISIS-controlled Al-Raqqa province in Syria and the Mosul district in Iraq off limits. Australians who travel to those regions face up to 10 years in prison.

Mulcair, who spoke to reporters in Vancouver, said that there is “very little evidence†that such a law could have a “concrete effect.â€

The NDP leader chided Harper for not “doing something concrete about radicalization of youth here in Canada,†when it introduced it Anti-terrorism Act, known as Bill C-51. The NDP voted against C-51 citing civil liberties concerns.

Mulcair said “we can all be a little skeptical as to whether or not there’s any real effect,†considering that the proposed law was announced during the election campaign.

“I don’t know of too many flights between Toronto and these war zones,†Mulcair added. “Most of them are going through other countries, so it won’t make a big difference practically speaking.â€

Security analyst Michael Zekulin told Â鶹´«Ã½ Channel that those going overseas to aid terrorist groups like ISIS are “already making every effort to ensure that their travel abroad is done surreptitiously†and that keeping track of “who is going where and what they’re doing … has always been the problem.â€

Zekulin said Canadians may question not only the enforceability of such a law, but whether a “reverse burden of proof†is “acceptable†for those with legitimate reasons, such as research or news reporting, to travel in terrorist-controlled territories.

Ron Myles, a former CSIS agent, told Â鶹´«Ã½ Channel that it “seems to be a bit of an oversight†that such a law wasn’t part of earlier legislation because it has proven difficult to arrest people who return to Canada from ISIS-controlled zones.

However, Myles said it would be “extremely difficult to prove†why a person travelled to such a place.

“How do you prove what somebody did in a zone where you have absolutely no information, or very limited information, and take these people to criminal court?†Myles said.

Myles added that would-be terrorists will find ways to take advantage of the exemptions, perhaps by disguising themselves as aid workers.

Liberal Leader Justin Trudeau, who spoke to reporters after a rally in Ottawa, said Canadians deserve to know more about how such a law might limit their rights, and that the announcement suggests, “Mr. Harper wants to talk about anything except that his economic plan has failed.â€