A. curvata has 3 black bars under the forewing in Laura's photo in http://lepidoptera.butterflyhouse.com.au/arct/curvata.html Maybe Tigrioides alterna, see http://lepidoptera.butterflyhouse.com.au/arct/arctiinae-under.html
A. curvata is quite different down here - much stonger orange colour and more significant black markings - haven't managed to photograph the undersides of one here. The other marker in common with this one is the black mid-underwing spot which is also in my Qld one
We know A. curvata can vary a lot in the degree to which the black markings are expressed in different specimens. A. curvata, after all, seems most likely to me, based on Dianne's photo, see second comment above. See also here:- Ardices curvata (Crimson Tiger Moth)