Unfair dismissal vs general protections: which claim fits your situation
Both run on the same 21-day deadline, but they ask different questions, and once you lodge one you generally cannot also lodge the other about the same dismissal.
The Fair Work Commission draws the line between the two claim types in its own words: "In an unfair dismissal case, the focus is on whether your dismissal was harsh, unjust or unreasonable. In a general protections case, you are saying that you were fired for a reason that is against the law." They are different questions about the same event, and the Commission's guidance states that once you have made one, you generally cannot also make the other about the same dismissal: "You cannot apply if you have already made another application. For example, if you have already made an unfair dismissal application or an application under anti-discrimination laws about your dismissal."
Same deadline, different destination if it does not settle
Both application types carry the same 21-day lodgement deadline, and both are tested against the same exceptional-circumstances standard for a late application. Where they diverge is what happens if conciliation does not resolve the case. An unresolved unfair dismissal application is decided by the Commission itself, usually at a hearing or conference. An unresolved general protections dismissal dispute normally moves to a court instead: the Commission issues a certificate allowing the case to proceed, and if the Commission Member thinks the applicant is unlikely to succeed at court, the certificate must say so. From there you generally have 14 days to apply to the Federal Court, apply to the Federal Circuit and Family Court, or, only if both sides agree, jointly ask the Commission to arbitrate. Commission arbitration of a general protections dispute is rare and needs both parties' signed consent.
Eligibility differs too
Unfair dismissal eligibility depends on the minimum employment period and the high income threshold, among other things. General protections claims about dismissal do not run on the same eligibility gate; the Commission's guidance frames them around whether the dismissal was for a prohibited reason, such as exercising a workplace right or a protected attribute, rather than around length of service or income. This site has not sourced the full list of protected attributes or workplace rights the general protections provisions cover, so nothing here enumerates them beyond this general description.