Canada's spy agency is expected to be given new powers to stop would-be Canadian jihadists before they leave the country as part of sweeping new anti-terrorism measures being unveiled Friday.

Sources familiar with the proposed legislation tell CBC News the goal is to give the Canadian Security and Intelligence Service the kinds of legal tools that are available to intelligence services in other Western countries.

The expected new powers would allow CSIS agents to obtain court orders to:

cancel plane or other travel reservations made by Canadians suspected of wanting to join the Islamic State or other extremists groups overseas;

block any financial transactions linked to suspected terrorist activity;

intercept shipments of Canadian-made equipment or material to Canadian individuals or groups that could be used in an attack;

switch, or make suspect equipment being shipped unusable as part of an on-going investigation.

Under existing law, CSIS must rely on the RCMP to do these things, and government officials say that can lead to costly delays and, in some cases, an inability to act because the RCMP requires a higher standard of proof to arrest or detain suspects.

Work on the bill began immediately after the Oct. 22 attack on Parliament Hill by Michael Zehaf-Bibeau.

The lone gunman stormed Parliament Hill after shooting Cpl. Nathan Cirillo as he stood guard at the National War Memorial.

Just two days earlier, Martin Couture-Rouleau used his car to run down Warrant Officer Patrice Vincent in Saint-Jean-sur-Richelieu, Que.

CBC News reported earlier this month that the RCMP had tried to obtain a peace bond against Couture-Rouleau a few weeks earlier but weren't able to muster sufficient evidence.

Power to disrupt

"The goal is for CSIS to move from an intelligence-gathering service to an agency that will have the power to disrupt or diminish potential terrorist threats under appropriate judicial oversight,'' a source told CBC News.

But CSIS agents will not be given the power to arrest or detain Canadians. That power will continue to reside with the RCMP and other police forces.

Expanding the mandate given CSIS is just one of many changes expected in the massive bill, which will have five distinct sections, to be tabled in the Commons on Friday. Prime Minister Stephen Harper will hold a news conference to discuss the measures later in the day.

Prime Minister Stephen Harper and York Regional Police Chief Eric Jolliffe take part in a discussion with law enforcement officials regarding issues related to national security in Aurora, Ont., on Thursday. New legislation is coming. (The Canadian Press)

"We are not under any illusion of the evolving multiple threats that we face," Harper said Thursday in Aurora, north of Toronto.

"It's difficult to predict them all, but we must continually evolve and improve our tools to do everything we can in what are obviously dangerous situations for the Canadian public, situations that we are seeing more and more frequently all over the world."

CBC News has already reported that the government intends to amend a number of laws to provide national security agencies with explicit authority to obtain and share information that is now subject to privacy limits.

Sources also confirm that the proposed legislation is expected to create a number of new criminal offences. Key among those is to make it an offence for anyone to "advocate or promote" terrorism online or through social media.

The law now makes it illegal for anyone to "counsel" someone to commit a terrorist act.

And the new bill is expected to extend the length of time police can detain a person without charge if they are suspected of being involved in a possible terrorist act.

Freedom of speech

Britain already allows anyone suspected of terrorism links to be detained for up to 14 days. Britain and France, in the wake of the massacre at the satirical magazine, Charlie Hebdo, earlier this month, are also looking at laws to make it easier to trace the identities of anyone promoting terrorist activities online.

Canadian civil rights experts have warned these kinds of powers may violate the Charter of Rights guarantees to security of person and freedom of speech.

But government officials say they're confident the proposed measures are consistent with Canadian law.

Even so, sources tell CBC News that work on the proposed bill continued into this week, as government lawyers wrestled with the Charter implications of the new powers.

Several investigations into the October attacks are still ongoing.

RCMP Commissioner Bob Paulson has told reporters that investigators recovered a video Zehaf-Bibeau made the day before the Ottawa attack which includes statements that show he was driven by ideological and political motives.

That video has not been released.