Yesterday, the office of Canada's Minister of Public Safety and Emergency Preparedness designated 13 groups as "Terrorist Groups". According to CBC, the result is that it is not necessarily a crime to be a member of a listed group. But banks and financial institutions can now freeze the group's assets, and police can charge anyone who financially or materially supports the group. Members seeking entry into Canada may be denied if they are found to be associated with a listed entity and the group's online content can be removed more easily.
I won't even state the groups' names here because my question is about a more general principle; what defense would an organization or an individual have against the state upon being designated as an affiliate to a terrorist organization? Regardless of what you may think of this specific instance, I think it is quite bizarre to have the state be able punish you with all that was stated above through essentially what is executive action (no legislation, or opportunity of defending oneself in a court). Any references to Common Law precedent as well as parallels in the USA would be appreciated.