Anti-terror provisions that have caused debate in the Liberal party and sparked a political ruckus in the House of Commons should be extended for three years, a Senate committee recommended Thursday.

But in its report, the special Senate panel chaired by Liberal David Smith asked that new safeguards be attached to two disputed provisions of the Anti-Terrorism Act, which are set to expire on March 1 unless they are renewed by Parliament.

The committee, which has been holding hearings for two years, heard from more than 100 witnesses.

The report acknowledged that the provisions "give the police more latitude to arrest and a judge more latitude to order the continued detention of the individual or impose restrictions on him or her."

But it noted that "protections were put in the legislation to ensure a certain amount of due process."

The senators said the provisions should be extended for three years and then be re-evaluated by parliamentary committees to determine whether they should be renewed.

The public safety minister must also note in his or her annual report when the extraordinary powers were used, whether they are still needed and why, the committee said. 

If the provisions are used in the future, the government should explain why ordinary Criminal Code measures couldn't be used, the committee said.

"Conversely, if the provisions remain unused, we ask the government to justify their continued existence or acknowledge that they should cease to apply," the committee said.

The Anti-Terrorism Act, which went into effect in December 2001 following the Sept. 11 attacks in New York and Washington, D.C., allows police to arrest people and hold them without charge for up to 72 hours if they're suspected of planning a terrorist act.

It also requires anyone with information relevant to the investigation of a terrorist act to appear before a judge for investigative hearings. Neither of these measures have ever been used.

Critics of the law say it goes too far and tramples on civil liberties. Those who support the legislation say it's an important tool in fighting terrorism.

Liberal Leader Stéphane Dion has said he opposes extending the provisions, and has demanded that Liberal MPs vote against the extension. The Bloc Québécois and NDP also oppose extending the provisions.

But some within the Liberal ranks believe the provisions should be kept, including former public safety minister Anne McLellan, former justice minister Irwin Cotler and former finance minister John Manley.

Prime Minister Stephen Harper, who supports the provisions, needs Liberal support to renew the legislation. He caused an uproar in the House of Commons on Wednesday when he implied the Liberals were voting against the provisions to protect one of their MPs.

During question period, Harper tried to raise a Vancouver Sun article that said the RCMP wants to use parts of the law to interview the father-in-law of Navdeep Singh Bains in connection with the Air India bombing.

Harper was shouted down. Dion later accused the prime minister of trying to smear an MP with a "base" partisan attack.

With files from the Canadian Press