Former Public Safety Minister Stockwell Day will testify in a long-running terrorism case this week, potentially opening a rare window into the inner procedures surrounding the labelling of Canadian terror suspects.

Day is scheduled to testify Thursday as part of the legal battle by Mohamed Mahjoub, an Egyptian who has been under house arrest or detention for more than a decade as a suspected jihadist, despite the fact he has not been charged in Canada.

Mahjoub is contesting the reasonableness of the security certificate, issued when Day held the public safety portfolio, that has enabled authorities to restrict his freedom.

Due to national security concerns, little is known about the secret criteria used to issue such certificates, and it is hoped that Day will shed some light on the murky decision-making process, said CTV legal analyst Steven Skurka.

"Until this moment there has been this wall of silence that has not been pierced about the label that the government has placed on terrorism suspects, people who aren't charged but are subject to being detained or under house arrest as the result of a security certificate," Skurka told CTVNews.ca.

He added there has been no accountability for those making the decisions, and no transparency regarding the process, something that "is going to fundamentally change with Stockwell Day's testimony."

He added: "As of this moment we know absolutely zero about the process, so I think it's going to be insightful, it's going to be a healthy exercise in democracy, it's unique to my knowledge in the Western world -- it certainly hasn't happened in America -- and it's going to happen without compromising our national security."

Skurka said Day is likely to be extremely careful about what he reveals, and will have consulted with federal lawyers ahead of time.

"Clearly we're going to see him raise some issues related to national security, but a blanket rejection of every question asked is very unlikely. I think the optics will be very poor if that happens."

A group calling itself "Support Mahjoub" called on supporters to come out and "see Stockwell squirm" at the hearing.

"It's rare to see political elites being held to account in court so this a not-to-be missed event. Make sure you come out, and let your friends know too," stated a post on the website supportmahjoub.com.

The organizers planned a "potluck teach-in" as well as performances to be held alongside the court appearance on Thursday.