Citizenship and Immigration Canada has confirmed it is "revoking and refusing passports to those going abroad to take part in terrorist activities."
Lorne Waldman, the head of the Canadian Association of Refugee Lawyers, says he's worried the government might use its powers arbitrarily.
Waldman likened the practice to Canada's secretive no-fly list, which civil liberties groups have argued violates the right to due process.
In the case of passport revocation, Waldman says there are at least legal avenues available for people to appeal such a decision through the courts.
But he said there should be assurances that power is used fairly by Citizenship and Immigration Minister Chris Alexander.
"The Passport Order gives the minister the right to deny passports if there were issues of national security," Waldman said Sunday.
"Now, that's pretty vague and pretty broad, and the minister is going to have to justify it in some way or another."
The measure comes amid growing concern about the potential for homegrown terrorism.
A Public Safety Canada report released last month said there were about 130 individuals suspected of terror-related activities abroad at the beginning of 2014. About 30 people with Canadian connections were suspected of terror activities in Syria.
In an emailed statement, Citizenship and Immigration Canada spokesman Kevin Menard said the government is "taking a strong stance against terrorism and we will revoke citizenship and strip passports from those who seek to harm our country."