OTTAWA -- The Conservative government alarmed privacy advocates by overhauling the law to give Canada's spy agency easier access to federal data, even though the spies themselves said greater information-sharing could be done under existing laws, newly released documents show.

In a presentation to federal deputy ministers last year, the Canadian Security Intelligence Service said "significant improvements" to the sharing of national-security information were possible within the "existing legislative framework."

The Canadian Press obtained a heavily censored copy of the secret February 2014 presentation and a related memo to CSIS director Michel Coulombe under the Access to Information Act.

Earlier this year, the government introduced an omnibus security bill that included the Security of Canada Information Sharing Act, intended to remove legal barriers that prevented or delayed the exchange of relevant files.

The legislation, which recently received royal assent, permits the sharing of information about activity that undermines the security of Canada, something law professors Craig Forcese and Kent Roach called "a new and astonishingly broad concept."

Privacy commissioner Daniel Therrien denounced the scope as "clearly excessive," saying it could make available all federally held information about someone of interest to as many as 17 government departments and agencies with responsibilities for national security.

In the 2014 memo to Coulombe, CSIS assistant director Tom Venner stressed the importance of timely and reliable information exchanges, and he lamented the patchwork of existing authorities that hindered sharing.

"The absence of a clear authority to share information for national security purposes amplifies this challenge," he wrote in preparing Coulombe for the meeting with deputies.

"Generally, information sharing with (other government departments) is carried out on a case-by-case and/or ad-hoc basis, which is antiquated and inefficient."

However, he added that laws and arrangements "often allow for the sharing of information for national security purposes," and that further strides could be made with "appropriate direction and framework in place."

Venner cited a number of recently successful pilot projects and outlined "future opportunities" for sharing -- all of them deleted from the memo.

CSIS clearly saw "room for workarounds" in the existing law "with a little bit more co-ordination within government," Forcese said in an interview.

The spy agency's memo seems "to belie the whole justification for the controversial information-sharing regime" in the government's subsequent anti-terrorism bill, said Forcese, who teaches at the University of Ottawa.

NDP public safety critic Randall Garrison said Wednesday the party opposed the bill because it was clear the powers were unprecedented, excessive and lacked oversight.

"Now we learn that the Conservatives weren't truthful when they told Canadians that these laws were necessary," he said.

Jeremy Laurin, a spokesman for Public Safety Minister Steven Blaney, would not say precisely why the government chose to go further on information-sharing than CSIS had advocated early last year.

However, Laurin said Canadians would expect that if one branch of government is aware of a threat to their security, this information would be shared with other branches to protect the public.

He also noted that Coulombe endorsed the planned information-sharing changes during April testimony before a Senate committee, particularly a provision allowing agencies to pass along information to others without first being asked.

"For us it's essential because, at the moment, we have to rely on us asking another department if they have information, but it's difficult to ask something that you're not aware of," Coulombe told senators.

Redactions make it difficult to fully understand the records released under the access law, said Keith Stewart, an energy campaigner with Greenpeace Canada.

But it appears the Harper government gave CSIS even more than it was seeking when the omnibus security bill greatly expanded the range of information that could be shared, said Stewart, whose organization remains concerned the new law will be used to target those who oppose fossil-fuel industries.

"This reinforces the arguments of those who say that this bill is really a form of crass electioneering that sacrifices our rights and freedoms without making us any safer."

The government still hasn't made a case for dismantling barriers to information-sharing, said Carmen Cheung, senior counsel at the B.C. Civil Liberties Association.

"Where is the necessity for these laws? Why do we need them?"