Privacy Commissioner Daniel Therrien says he is concerned that the government’s new anti-terror bill does not respect the privacy rights of Canadians.

Bill C-51 proposes to lower the threshold of what’s required for police to make an arrest in a terror case. Previously an arrest could be made only if a terror act “will be” carried out, but C-51 would allow police to arrest a suspect if an attack “may be” about to happen.

It would also broadly expand the powers of Canada’s spy agency, CSIS, to “counter-message” or “disrupt” terrorist websites, Twitter accounts and the like.

“This Act would seemingly allow departments and agencies to share the personal information of all individuals, including ordinary Canadians who may not be suspected of terrorist activities, for the purpose of detecting and identifying new security threats,” Therrien said. “ It is not clear that this would be a proportional measure that respects the privacy rights of Canadians.”

Therrien said Canadians want to be safe but they also care profoundly about their privacy rights.

"They also want government to be more transparent on the activities they undertake in the name of national security and they want to know why these are necessary, he said.

But Prime Minister Stephen Harper insisted jihadists, and not his bill, are the real threat to Canadians’ freedoms.

Parliament Hill reporters covering the bill weren’t provided with a copy of the legislation until moments before it was tabled Friday. Asked whether the bill threatens charter rights, Harper responded: “It’s the jihadis who would take away our freedoms.

“They want to harm us because they hate our society and the values it represents.”

NDP foreign affairs critic Paul Dewar said “terrorism is a real threat to society,” but he’s concerned about a lack of “commensurate” oversight of CSIS along with the expansion of its powers.

“If you’re expanding (security agencies’) powers, you need commensurate oversight,” Dewar said. “This government isn’t taking present oversight obligations seriously.”

— With files from Jessica Hume