At the request of authorities, a court issued a control order against Melbourne man Jack Thomas on Monday, which restricts what he can do and where he can go.
One of Mr Thomas' lawyers, Mr Rob Stary, says his client is not a threat to the community.
"They need to show that it is reasonably necessary to protect the community from a terrorist attack," he said. "And that is also an issue that will be hotly contested. We say there is absolutely no foundation for such an order in Mr Thomas' case."
A preliminary hearing will be held later this week challenging Mr Thomas' control order.