The federation has said it will apply for leave to argue that two government bills are unconstitutional.
The bills are part of a giant overhaul of Saskatchewan's labour legislation, but are not yet included in a new labour act that was passed in May.
One of them would bar workers deemed to be essential from striking.
The other involves changes to the Trade Union Act.
Unions have been particularly outraged by the essential services bill, which has been challenged at several court levels.
A Court of Queen's Bench judge ruled in February 2012 that the law — which was originally passed in May 2008 — was unconstitutional.
But the Saskatchewan Court of Appeal ruled in April that the right to walk off the job is not protected by the charter.