Canada's spy chief backs the Conservative government's troubled bid to bolster Internet surveillance powers, and has offered to help tweak the legislation to make it more palatable to a wary public.

In a letter to Public Safety Minister Vic Toews, Canadian Security Intelligence Service director Richard Fadden says the spy agency was "extremely pleased" to see the bill come before Parliament, considering it "vital" to protecting national security.

CSIS was drafting "potential options" to strengthen accountability measures in the bill, says the late February letter, sent to the embattled minister following a wave of opposition to the legislation from civil libertarians and Internet privacy advocates.

The Canadian Press obtained a declassified version of the top secret letter this week under the Access to Information Act.

The federal legislation would allow police, intelligence and competition bureau officers access to Internet subscriber information — including name, address, telephone number, email address and Internet Protocol address — without a warrant. An IP address is the numeric label assigned to a computer on the Internet.

It would also require telecommunication service providers to have the technical capability to enable police and spies to intercept messages and conversations.

"Of the various provisions contained in the bill, the intercept capability requirements are of primary importance to the Service and critical to national security," Fadden says in the letter.

There have been cases in which such technical barriers prevented CSIS from carrying out surveillance authorized by Federal Court warrant, he says. Operations are also jeopardized when communication networks "go dark" — including one unexpected outage that lasted over a week, Fadden adds.

Concerns over privacy, cost

The RCMP has said that police must often engineer interception solutions before they are able to execute a court order, meaning sometimes they are unable to tap into communications.

Fadden acknowledges the cost for companies to set up and maintain intercept-capable networks could be significant. But he argues the legislation provides "generous lead times and grandfathering provisions" that will help industry.

Opponents of the bill say allowing authorities access to Internet subscriber information without a court-approved warrant would be a dangerous infringement of privacy because even that limited data can be revealing.

"This is all stuff that can together give a pretty solid road map of what you are doing online and who you are talking to," said Lindsey Pinto, spokeswoman for OpenMedia.ca, which promotes an open, affordable Internet and has vociferously lobbied against the bill.

"Based on that kind of information, it is fairly easy to see what kind of website somebody is visiting, who they're in touch with, what their social media profiles are."

Fadden urged the government to address the issue.

"Concerning basic subscriber information (BSI), the Service would welcome any efforts to clarify that the content of users' communications, including web browsing, may still only be obtained with a warrant."

CSIS helping 'strengthen' bill

Still, Fadden says CSIS would lend a hand by drafting "potential options to strengthen the accountability regime on the BSI provisions of the bill."

Ultimately these provisions "would bring legislative clarity, predictability and accountability to an important investigative practice," Fadden adds.

CSIS spokeswoman Tahera Mufti said the spy service did provide advice to the minister but she declined to say more.

"I will not comment on the details of this exchange or further elaborate on our position with respect to this legislation."

When concerns about the bill arose in the Commons shortly before its introduction, Toews told a Liberal MP he could either stand with the government or "with the child pornographers" prowling online.

His comment drew widespread denunciation.

Amid the furor, the government indicated a willingness to amend the legislation by sending it straight to committee for study instead of the usual second reading in the House of Commons. However, the bill did not resurface before the Commons rose for the summer.

Fadden's letter makes it clear he is eager to see the legislation re-emerge.

"The Service remains available to support this process through all legislative stages and we view this legislation as vital in our ability to protect Canada's national security in a world of rapidly evolving technology."