OTTAWA—Canada’s spy agency is using controversial powers under the C-51 anti-terrorism legislation to gather intelligence from Canadians held in foreign prisons, a newly released memo reveals.

Amnesty International Canada and the NDP are expressing concerns about the potential pitfalls of the previously unknown information-sharing arrangement between the Canadian Security Intelligence Service and Global Affairs Canada.

The spy service and Global Affairs made the sharing deal this year through the Security of Canada Information Sharing Act — part of the omnibus security legislation known as C-51, says a secret memo to Public Safety Minister Ralph Goodale from CSIS director Michel Coulombe.

The provisions, ushered in by the previous Conservative government, expanded the exchange of federally held information about activity that “undermines the security of Canada.”

“Information collected by (Global Affairs Canada) through the provision of consular services can be directly relevant to investigations of threats to the security of Canada,” says the heavily censored CSIS memo, obtained by The Canadian Press under the Access to Information Act.

However, it is often difficult for consular officials to determine when a detained Canadian has been tortured and what impact that has on the information they may be sharing, said Alex Neve, secretary general of Amnesty International Canada.

That became glaringly evident in the case of Maher Arar, an Ottawa communications engineer who made false confessions of terrorist involvement while being tortured by his captors in a Syrian prison, Neve noted.

In general, the new arrangement seems based on an understanding that information obtained by consular officers while working with or interviewing Canadians detained abroad “can and will be shared with CSIS when relevant to national security,” Neve said.

“That gives rise to very obvious concerns about the privacy rights of individuals receiving consular assistance.”

Justice Dennis O’Connor, who led a federal inquiry into the Arar case, recommended that consular officials clearly advise detainees in foreign countries of the circumstances under which information obtained from them may be shared with others outside the consular affairs bureau, before any such information is obtained.

Privacy commissioner Daniel Therrien warned this month the government hadn’t done enough to protect “law-abiding Canadians” from exchanges under the Security of Canada Information Sharing Act.

In his annual report, Therrien said the law is broadly worded and leaves much discretion to agencies to define what sort of activities undermine security.

The sharing arrangement between CSIS and Global Affairs underscores the concerns raised by the privacy commissioner and reaffirms the NDP’s desire to see C-51 repealed, said Matthew Dube, the party’s public safety critic.

“The appropriate safeguards aren’t in place.”

Neither Global Affairs Canada nor CSIS would provide details about the sort of information the spy service hoped to obtain through the new sharing arrangement.

Both agencies say they carry out their duties in accordance with relevant legal and privacy obligations.

The C-51 provisions are intended to improve domestic information sharing for national security purposes while respecting the privacy rights of Canadians “no matter where they are,” said Global Affairs spokeswoman Kristine Racicot.

The Liberals have promised to fix “problematic elements” of C-51, and Goodale recently launched public consultations on the overall national security framework.