Although normally yellow, some white specimens of this species are illustrated in https://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:49cd388d-3721-4e42-a6a1-ab012cdf4954 However this sighting is a long way south of it's usual southern limit. Wow.
I see the strong similarity with the whiter examles of A. astrea on the ALA, but there seems to no hint of yellow at all in this specimen, the dots to me seem smaller and to me have a subtly different pattern; and the aetennae are black on the ALA.
However: the pattern of the spots is a good match. Drury said there are 40 spots on each forewing of his specimen (presumably the holotype). Christine: how many does yours have, ?
I suggest the spotting pattern and tha overall shape in outline of the moth better fits Utetheisa sp. (genus). We have recorded similar sightings before showing no red markings, even photographed on the same plant, Echium sp.(genus), see Sightings No. 4353705, 4253477 and 4256666.