OTTAWA - Supporters are speaking out on behalf of Mohamed Harkat as he heads to court to try to end Canada's security certificate regime.

Harkat faces deportation to his native Algeria under a security certificate that declares him a threat to Canada due to alleged terrorist links.

A judge ruled in 2010 that the certificate system was constitutional -- a decision Harkat will challenge next week in the Federal Court of Appeal.

Alex Neve of Amnesty International Canada argues the security certificate process remains flawed and unfair despite changes ushered in four years ago.

Green Party Leader Elizabeth May says the certificates -- used to deport non-Canadians who are considered a security threat -- represent an affront to all Canadians.

Harkat, a former Ottawa gas attendant and pizza delivery man, was arrested more than nine years ago on suspicion of being an al-Qaida sleeper agent.