Former CSIS chief Reid Morden says he's 'sorry to hear' the government is rekindling two contentious anti-terrorism measures. (CBC)

Canada's former top spy has slammed the government's fourth attempt to revive two fiercely debated parts of the Anti-terrorism Act, saying he "never thought" they should have been enacted in the first place.

The provisions would give police extraordinary powers of preventive arrest and could force people to show up at secret hearings to testify about possibly pending criminal acts, under penalty of imprisonment. Justice Minister Rob Nicholson touted the measures on Friday as necessary tools to fight terrorism.

The provisions had a five-year sunset clause when Parliament passed them as part of Canada's original 2001 anti-terrorism law following the Sept. 11 hijackings in the United States that year. They expired in March 2007 when the Commons voted down a Tory motion to renew them, but not before the Conservatives painted the Liberal opposition as soft on terrorism.

The government tried to reintroduce the clauses before the 2008 election and again last year, but both times they failed to become law before the parliamentary session ended.

Justice Minister Rob Nicholson says the provisions are 'necessary to protect our country.' (Canadian Press)

Nicholson rekindled the clauses Friday as part a new bill, saying in a statement that they "are necessary to protect our country from the threat of terrorism."

Not so, said Reid Morden, who was director of the Canadian Security Intelligence Service for four years ending in the early 1990s.

"Speaking strictly of those two particular provisions, I confess I never thought that they should have been introduced in the first place and that they slipped in, in the kind of scrambling around that the government did after 9/11," Morden said.

"It seemed to me that it turned our judicial system somewhat on its head," added Morden, who also served as deputy minister at Foreign Affairs and eventually was awarded the Order of Canada. "I guess I'm sorry to hear that the government has decided to reintroduce them."

Never used

One of the anti-terrorism measures allows police to pre-emptively arrest suspects without a warrant and detain them for three days without charges, provided police believe a terrorist act may be committed. The other measure allows judges to compel witnesses to testify in secret if it's believed the person has information relevant to the investigation of a pending terrorist act. The witnesses could go to jail if they don't comply.

Neither provision was ever used.

Nicholson said he is confident they will be adopted by Parliament this time around.

Liberal justice critic Mark Holland sounded a more conciliatory note Friday, saying his party might be willing to support the new bill as long as it's carefully studied first by the Commons justice committee.

Holland said the Liberals were assuaged by amendments proposed last year by a Senate committee that added safeguards to civil liberties.

But Holland said the Liberals don't plan to rubber stamp the bill, either.

"We have to make sure that police agencies have every tool at their disposal that's reasonable and doesn't unfairly impinge upon individual rights," he said.

"We've got to study this issue carefully at committee and ensure that it doesn't go too far."

With files from The Canadian Press