Top privacy advocates are calling for rules to govern how government employees access Canadians' social media posts, following the revelation that the Canada Revenue Agency checks posts on social media sites like Facebook to catch tax cheats.

Privacy commissioner Daniel Therrien and former assistant commissioner Chantal Bernier say the Treasury Board should draft guidelines.

"We understand the TBS is in the process of reviewing government policies and we would encourage them to consider this issue as part of that review," Tobi Cohen, spokeswoman for the commissioner's office, said in an email.

Cohen said government officials should only collect information if it directly relates to a government program.

"Departments and agencies should take care to ensure the accuracy of information that is collected. We would also encourage government institutions to be transparent and up front with Canadians when it comes to their data collection practices," Cohen wrote.

Meanwhile, she said Therrien is urging Canadians to be careful about their privacy settings and what they post.

Privacy commissioner Daniel Therrien says the government should draft rules to govern government officials consulting the social media posts of Canadians. (Sean Kilpatrick/Canadian Press)

Bernier, who now works as a lawyer with the firm Dentons, says it is "urgent" for the government to act.

"It has become a normal manner to gather intelligence. So we absolutely must give it a framework. We absolutely must clarify what the limits are."

Jean-Luc Ferland, spokesman for Treasury Board President Scott Brison, says the government is conducting a review of Canada's Privacy Act. Once that review is finished Treasury Board will consider guidelines.

"Our government will work with parliamentarians, stakeholders and interested Canadians to ensure we have strong and modern privacy rules that reflect Canadians' needs and expectations," he said, adding the Privacy Act has not been substantially changed since it went into effect in 1983.

However, he would not say whether the review will examine the practice of government officials accessing social media posts.

'Publicly available information' and privacy

CBC News reported last week that the Canada Revenue Agency's compliance section is scrutinizing the social media posts of Canadians it suspects are at "high risk" of cheating on their taxes. Among those the agency considers at high risk are wealthy individuals who have offshore bank accounts.

The agency defends the practice, saying it is simply using "publicly available information." However, privacy advocates point out that Canadians can often find that something they thought they were only sharing with their family and friends is publicly visible.

Bernier, who served as interim privacy commissioner and assistant privacy commissioner, says the CRA isn't the first government body to dig into Facebook posts.

In a 2013 report, the privacy commissioner's office found the Justice Department and the department of Aboriginal Affairs and Northern Development Canada violated First Nations activist Cindy Blackstock's privacy by monitoring her personal Facebook page.

Former assistant privacy commissioner Chantal Bernier says it is "urgent" for the government to clear up the rules. (Sean Kilpatrick/Canadian Press)

The privacy commissioner's office concluded that the fact the posts were publicly available did not trump Blackstock's privacy rights.

Bernier said the government needs to clarify three legal notions when it comes to federal officials accessing Canadians' social media posts:

What is meant by publicly available information. When the Privacy Act was drafted, publicly available meant information that was directed at the public through things like books or pamphlets, she said.

The act's requirement that information should be directly collected from individuals. "How does that impact departments' right — or not — to access open-source information?"

What kind of scrutiny is considered directly related to the government's activities or programs.

Catching tax cheats

"Because it is on your Facebook page, and even if you have 800 friends, you have not surrendered your right to privacy by putting that information on your Facebook page. It remains personal information, therefore it remains protected by the Privacy Act, which means the government cannot collect it unless it is directly related … to its operations, and it should be done with at least transparency."

Others, however, like Scott Chamberlain, chairman of Canadians for Tax Fairness, don't want to see privacy concerns prevent CRA from catching people tax cheats.

Lawyer Scott Chamberlain, chairman of Canadians for Tax Fairness, says privacy concerns should not impede the Canada Revenue Agency's ability to do its job. (Parliament of Canada)

"I'm not against looking at implementing rules about when people should be doing this, but I think it needs to be done in a context where there are professionals — academics, lawyers, government people — who understand the balance between privacy and CRA being able to do its job."

Chamberlain, a lawyer, said CRA has long used publicly available information to investigate tax fraud, such as taking pictures of a yacht or high-priced car that didn't match tax records parked in front of someone's home.

"If it's publicly available, CRA has always investigated. It's just that it's publicly available online now."

Elizabeth Thompson can be reached at elizabeth.thompson@cbc.ca