The Conservative government introduced legislation in the House of Commons on Monday that will change the way its controversial security certificates are handled.

The certificates allow Canada to detain and deport foreign-born terrorist suspects who are deemed a threat to national security.

Federal Court judges approve the certificates based on secret intelligence evidence presented at a private hearing that suspects and their lawyers are not allowed to attend.

The new security certificate law bill is expected to give detainees access to a special advocate who will represent them at the private hearing.

"That would be someone appointed by the government or the court, someone with top security clearance, who could act as a go-between between the detainee and the court," the CBC's Rosemary Barton reported from Ottawa on Monday morning.

Five men are currently the subject of security certificates — four have been released on strict bail conditions, while suspect Hassan Almrei is still in custody.

Almrei, who was born in Syria and came to Canada as a refugee in 1999, has been held without charge since October 2001. The government claims he was part of a forgery ring linked to al-Qaeda, but has not released the evidence against him.

The new bill comes after the Supreme Court of Canada ruled in February that the certificates violate the Charter of Rights and Freedoms. The court gave the Canadian government one year to rewrite the law relating to the certificates.

Security certificates, first introduced in Canada in 1978, have been the subject of heightened debate in the wake of the Sept. 11 attacks on the United States.

Suspects named in a security certificate do not get the chance to testify before a Federal Court judge after a closed-door hearing has taken place. The suspect is only provided with evidence against him or her that the judge has ruled can be safely released without providing a threat to national security.

The element of secrecy in the process may not change under the new bill, Barton reported.

Lawyer anxious to learn details of special advocate

Paul Copeland, a lawyer who represents two men held on security certificates, told CBC News before the bill was tabled on Monday that he is anxiously waiting to see how the special advocate's role will be defined.

Copeland said that if the advocate gets access to the secret evidence, and has a chance to consult with the suspect and challenge the evidence, the new bill could be a welcome change.

"But if [the Conservatives] come forward with a bare-bones model that is really assigned to do as little as possible … it will be a useless piece of nonsense."

Copeland said Great Britain allows special advocates under its security certificate laws, but the advocates have been quitting because they feel the rules are too restrictive to allow them to accomplish anything.

Critics have long called the certificates unjust, because suspects can face years in jail while a case works its way through the legal system. In the end, they could face deportation to countries with a record of torture.

The government maintains the certificates are crucial to national security.

Marches highlight certificate controversy

On the weekend, a spokeswoman for Public Safety Minister Stockwell Day stressed that the certificates are not issued without careful consideration.

"The only way a person could be subject to a security certificate would be a person that is not a Canadian citizen who represents a serious threat to Canada," Melisa Leclerc wrote in an e-mail to the Canadian Press.

She said the new anti-terrorism legislation will address the issues the Supreme Court asked the government to give attention to.

Her comments came as demonstrators staged marches in about a dozen Canadian cities on Saturday, demanding the government immediately withdraw the security certificates that have been issued.

Demonstrators also demanded an end to deportation proceedings that are currently underway against the five suspects.