A federal watchdog committee is set to begin a round of secret hearings to probe complaints that Canada's spy agency, the Canadian Security Intelligence Service, has been illegally snooping on environmental activists working against oil pipeline projects.

In 2014 the British Columbia Civil Liberties Association (BCCLA) filed two complaints against CSIS and the Royal Canadian Mounted Police (RCMP) accusing both agencies of spying on environmental and First Nations groups who were organizing against the Enbridge Northern Gateway pipeline, which would carry crude west from Alberta to BC. The groups allegedly subjected to surveillance include the Sierra Club of BC, the Dogwood Initiative, and ForestEthics Advocacy.

"This kind of activity, what's being alleged, has no place in democracy. The government and its spy agencies should not be busy surveilling and gathering intelligences on citizenships who are simply living their lives and participating in their communities," Josh Paterson, BCCLA's executive director, told VICE News. "There are plenty of undemocratic countries where governments spy on people they don't agree with. And Canada should not be one of them."

The BCCLA's complaints, based on government documents obtained under access to information requests, further allege the spy agency also shared their intelligence about "radicalized environmentalist" groups with the National Energy Board.

CSIS has long denied the BCCLA's allegations. "CSIS investigates — and advises government on — threats to national security, and that does not include peaceful protest and dissent," a CSIS spokesperson told the CBC last year.

New federal anti-terror legislation, known as Bill C-51, that recently came into force gives CSIS more powers to probe and disrupt extremist activities and has raised further worries that environmental and aboriginal groups in Canada could be subjected to more surveillance than ever before.

This week, the Guardian reported on the great lengths the Conservative government has undertaken to protect two major pipeline projects — Northern Gateway and Kinder Morgan — from environmental and First Nations groups. According to documents obtained under access to information by Greenpeace, the government is spending $30 million over two years on domestic and international "outreach activities" to promote the oil sands industry in Alberta. That's on top of the $22 million the government spent in 2014 on a similar ad campaign in the US.

The three-day hearings held by the committee that oversees CSIS start today in Vancouver and are shrouded in secrecy — media and members of the public are barred from attending. This afternoon, Paterson will testify for the complainants. And tomorrow, witnesses from groups allegedly spied on will testify about their experiences.

But it's unclear when CSIS will argue its side. As part of its disclosure ahead of the hearings, Paterson says CSIS has provided only printouts from its website and has said that a senior spy service manager, known only as "Robert," will testify at some point.

CSIS did not immediately respond to a request for comment from VICE News.

"It's so secretive that we likely won't know until after it has taken place and it makes this whole hearing super bizarre as an accountability mechanism. We have no ability to know what CSIS' argument is, what their evidence is, we can't respond to their arguments, our lawyers are not able to interact with what CSIS is saying," said Paterson.

He added that the BCCLA is not suggesting that a hearing about spying should never be held in secret, especially if there are legitimate concerns about national security or if it would put people in danger. "But here, the government's documents have made clear that there was no threat, that there was no question that these groups were engaged in anything other than peaceful activities. And so we really question why more information can't be disclosed by CSIS about what they were doing."

Last week, Alexandra Swann, a volunteer with the Dogwood Initiative, opened up about how the purported spying revelations have impacted her activism.

"Finding out had a chilling effect for me. Suddenly, I was very concerned how far it had extended," she wrote on the BCCLA's website.

"Was I personally named somewhere? Had they investigated my online activities? Read my emails? I realized the right to privacy was a myth in this country, and that being a decent person was no barrier to illegal scrutiny by people far more powerful than me."

Paterson said that witnesses will testify that the allegations about widespread CSIS surveillance has turned many people off from community activism.

"We're going to be hearing evidence from witnesses who say people are refusing to sign petitions because they don't want their names out there because they're worried about what security agencies might do," he said.

"We're also going to hear evidence from a new Canadian hoping to have Canadian citizenship who also didn't want to sign a petition because she was afraid of upsetting the government. And others who were fearful of volunteering with community organizations because it might draw unwanted attention from community organizations.

The BCCLA says it will consider asking the oversight committee to issue summonses to the CSIS employees listed on the documents.

The committee's probe is expected to take more than a year.