Public Safety Minister Steven Blaney gave Canadians a preview last week of his bid to boost the powers of Canada's spy agency, the Canadian Security Intelligence Service.

He wasn't able to reveal the full scope of his legislative initiative, of course — he can't do that until the bill is tabled in the House of Commons, which is expected to happen when MPs return to Ottawa next week.

But Blaney, who was joined on Thursday by senior officials from both CSIS and the RCMP, shared the highlights, including new provisions to allow the agency to track "homegrown" extremists abroad and extend witness protection to confidential sources.

"Now, more than ever, a radical individual or group of motivated extremists with access to technology can do significant harm to Canada from thousands of miles away," he told reporters.

But could the government's move to expand the existing anti-terror regime in an atmosphere of ISIS-inspired fears discourage MPs — particularly those in the opposition — from exercising full parliamentary due diligence?

"Even in the best of times, critiquing measures purportedly to protect us from terrorist threats is very difficult, both publicly and politically," B.C. Civil Liberties Association senior counsel Carmen Cheung told CBC News.

"I think that right now, given the very serious concerns that we in Canada and people around the world have about ISIS, it's going to be even harder."

Shrinking oversight mechanisms

"It seems like what they're trying to do is get around the gap in the CSIS Act that was identified by Justice [Richard] Mosley in his decision — they're basically allowing CSIS to operate overseas in a way that the current act doesn't," she noted.

In a landmark ruling handed down last year, Mosley concluded CSIS had misled the court on the "scope and extent" of its efforts to get foreign intelligence agencies to spy on Canadians.

"That was a deliberate decision that was made by Parliament to not have CSIS be like the CIA, for example, and limit its scope," Cheung said.

At the same time, she said, the government hasn't acted as quickly on oversight mechanisms called for by Justice Dennis O'Connor's judicial inquiry into the treatment of Maher Arar.

Arar, an Ottawa telecommunications engineer, was wrongly accused of terrorism and deported to Syria, where he was tortured. In his report, O'Connor recommended better oversight on how the RCMP shares information with foreign intelligence agencies.

"One thing we learned from O'Connor is that the bigger we grow our national security apparatus, the bigger we have to grow our review mechanisms. But instead of seeing any sort of corresponding growth in oversight or accountability regimes, we're just seeing them shrink and shrink and shrink," Cheung said.

May 'very concerned'

Green Party Leader Elizabeth May said she's "very concerned with the steady erosion of civil liberties" in Canada — beginning with anti-terrorism measures introduced by Prime Minister Jean Chrétien's Liberal government in the wake of the Sept. 11, 2001, attacks.

That bill "passed with a sunset clause," she noted. "The sun has risen again."

For May, a lack of federal oversight compounds those concerns.

"Mention 'terrorists' ‎ and ISIS, and many people will want to tear down civil liberties, but if the laws can invade the privacy and rights of any Canadian citizen, it's more worrying," she added.

"Once we give up our rights and liberties, it's very hard to get them back."

'Checks and balances' needed

Independent MP Brent Rathgeber agrees that the current international crisis and threat of homegrown terror "will provide cover for the government to expand the roles of CSEC and CSIS, and what they share with the Five Eyes."

The Five Eyes is the collective name for Canada and its intelligence-sharing allies — the U.S., Britain, Australia and New Zealand.

Rathgeber stressed some of those powers may very well be necessary, "given that the ISIS threat must be taken seriously."

The issue, he said, is to balance those national security concerns with privacy rights.

"Security agencies unchecked will grow both in times of imminent threat and in times of comparative security," he told CBC News. "Therefore it is incumbent on civilian oversight and Parliament to provide checks and balances."

Even so, he said he's not expecting to see any increased oversight powers in the new bill — and "given the legitimate climate of fear, or at least concern," he said, "the public will be complacent."

No need for 'duplicative' oversight

By a twist of procedural timing, MPs may find themselves with an opportunity to debate greater oversight when a private member's bill, sponsored by Liberal defence critic Joyce Murray, comes before the House this fall.

The bill would create a special parliamentary committee to monitor legislative, regulatory, policy and administrative framework for intelligence and national security in Canada, and review activities of all federal agencies, including CSIS.

Murray told CBC News she "has no problem in principle" with giving CSIS more leeway to keep track of suspected terrorists abroad.

But she's not ready to give up on transparency and accountability.

"The absence of parliamentary oversight and review mechanism for our security agencies means an absence of accountability to the Canadian public."

She'll need to the support of the government to pass her bill, however, which doesn't seem to be forthcoming.

"There is robust oversight of national security agencies in Canada," Public Safety spokesman Jason Tamming told CBC News.

"We are always focused on protecting the rights of Canadians," he said, adding the government appointed a former Ontario NDP MPP to the civilian oversight body in 2009.

"We don't need to strike any new committees to create duplicative oversight."