Australia government decision: how do I know if the ART can review it?

Check the decision letter first. Review rights depend on the law governing the particular decision, and the letter should usually explain whether review is available, which body can review it and any time limit. The Administrative Review Tribunal application process asks when you received the decision so it can check timeliness. Official source: Administrative Review Tribunal. Guide: https://getinstantlaw.com/government-decisions-appeals