Defence Minister Peter MacKay says Canada’s own secretive online and phone metadata surveillance program is "prohibited" from looking at the information of Canadians and is directed at monitoring foreign threats.

MacKay responded Monday to a Globe and Mail report that stated he had approved a program in 2011 that tracks the data surrounding online activity and phone calls searching for suspicious activity, but not the messages themselves.

NDP Leader Thomas Mulcair asked MacKay in question period on Monday if the Conservatives were monitoring the phone and email records of Canadians.

"Let me be very clear, this program is specifically prohibited from looking at the information of Canadians," MacKay responded. “This program is very much directed at activities outside the country, foreign threats in fact.”

The program was initially brought in by the former Liberal government in 2005, but was later put on hiatus over concerns it could lead to warrantless surveillance of Canadians. The Globe reports the program was quietly reinstated on Nov. 21, 2011 after MacKay signed a ministerial directive, which is not subject to parliamentary scrutiny.

Under the Anti-Terrorism Act, only the Communications Security Establishment Canada (CSEC), which is an arm of the Department of National Defence, can actually eavesdrop or monitor online communications.

It is believed that the Canadian program is used to monitor metadata both domestically and internationally. That means the CSEC could look at information such as email paths, senders and recipients, IP addresses and phone connections -- data that could help identify potential criminal networks or potential terrorist groups. But actual messages exchanged between individuals in those networks would be off limits unless a warrant was obtained.

According to the former Canadian Security Intelligence Service (CSIS) counter-intelligence chief, metadata is the information which frames a communication.

“It’s not the content but it’s the who, the length of time, the where, and it’s the when of a communication,” Geoffrey O’Brian told CTV’s Power Play on Monday.

O’Brian described the metadata surveillance program as a tripwire for suspicious activity which has the ability to alert police and security officials to potentially dangerous individuals or groups.

"If (CSEC) feels the need to look more intrusively, that’s when electronic surveillance kicks in," he said.

O’Brian added, however, that in order to proceed with electronic surveillance, there was a number of checks and balances in place.

"For CSIS, you need the personal approval of the director, the minister of public safety and a judge," he said.

According to MacKay there is “rigorous” oversight and legislation in place that dictates what can and cannot be monitored.

He noted that the CSEC commissioner found that the activities of the program “were carried out in accordance with the laws, ministerial requirements and CSEC policies."

But despite the government’s reassurance that there are protocols in place that protect the privacy of everyday Canadians, some critics have expressed concern about the program’s lack of transparency.

"There’s a whole lot of secrecy associated with this," Michael Geist, the Canada research chair in Internet and e-commerce law at the University of Ottawa, told CTV News.

"It’s not really clear what kind of oversight exists as part of this to ensure that it is only used to the extent which it is supposed to be used."

Last week it emerged that a similar program is in place in the U.S., run by the National Security Agency, allowing officials to track and analyze Internet data trails and communications as well as phone records. Similar to the Canadian program, the surveillance focuses on metadata as opposed to actual communications.

The U.S. program, called Prism, allegedly gives the NSA access to data from nine U.S. Internet companies, including Google and Facebook. As a result, Canadians who use those sites could also be included in the surveillance, experts say.

New Democrat Jack Harris noted on Monday that the U.K. government had committed to report about their use of Prism in British parliament, and asked if Canada follow suit.

MacKay responded by saying that the Conservatives have tabled reports on their monitoring program "for years."

"CSEC does not target the communication of Canadians," MacKay stressed. "This is foreign intelligence. This is something that has been happening for years."