H. australiae is undoubtedly widespread in Australia. It is likely also present in New Zealand, together with parts of Indonesia and a few other Australian Islands, but some of its observations may actually have been of a very similar related species, Hemicordulia armstrongi, recently recognized and documented in a 2019 paper by Rowe. Our single 2017 encounter in New Zealand was actually with H. armstrongi.
My 2019 trip to Queensland produced frequent observations of the real H. australiae, where I got a lot of practice snagging it in flight. They settle only occasionally. None of these encounters appear to have been H. armstrongi. I’ve included a poor shot of a female because one difference of these two sibling species is said to be the wings of the female, being hyaline in H. armstrongi. but tinted in H. australiae.