From The Australian Biosecurity Act 2015
What this means is that any health measures ordered by the health minister in the case of a pandemic have to be reasonable, appropriate, as non-intrusive as possible , for the shortest period possible and effective, otherwise they can and will be challenged in court. This is also determined by the charter of human rights.
The curfew has gone, and stringent hotel quarantine for all arrivals makes no sense anymore either, when there is community transmission, which is one reason why it’s about to be scrapped. Other measures like the 5 km rule and universal mask wearing are also being challenged by experts.
People can and will challenge the fines they received by breaching those measures and are most likely to win, which is why fines that have been put up for review are currently all dismissed, because if a precedent is set in court that the measure was disproportionate the government can be sued by all the people who received such fines. A class action is already being prepared by Serene Teffaha and her team at advocateme.com.au