https://www.pir.sa.gov.au/biosecurity/animal_health/bees/beekeeper_registration

This link from South Australia Primary Industries mentions registering top bar/warre/flow hives so I thing you would be ok. In the past many people believed top bar style hives were illegal because the regulations all reference the hives needing removable FRAMES, which of course top bars don't have. But the intent of the law is that the comb be removable for inspection, which is no problem in a maintained top bar. So i think it has been accepted that bars are an acceptable alternative to frames. But be sure and do your own research 👍👍