The Fair Work Act draws a sharp line.
Protected industrial action is lawful. It happens during bargaining for a new enterprise agreement, after a formal process. If it is protected, you are shielded from most legal consequences, your employer cannot sue you for losses caused by the action, and you cannot be sacked for taking part.
Unprotected industrial action does not carry those protections. Penalties can apply, and individuals and unions can be ordered to stop.
The short version: if you want the law on your side, the action has to be protected, and that means following the process.