What general protections are
Part 3-1 of the Fair Work Act makes it unlawful for an employer to take 'adverse action' against an employee for a prohibited reason. Adverse action includes dismissing you, injuring you in your employment, altering your position to your disadvantage, or discriminating against you. The central question in any claim is simply: why was the action taken?
The action is unlawful if a prohibited reason (such as you exercising a workplace right) was a substantial and operative reason for it. It does not have to be the only reason.