Similar, but seems to lack the same marginal black dots on the forewing and hindwing? https://www.inaturalist.org/taxa/466365-Idaea-inquinata Looking at BOLD Systems 4 'Idaea Australia' there a large number of named and un-named possibilities in the genus. I'm nit sure it matches BOLD Idaea sp. 14 given that specimen's large black dot.
I am confused about what dots are lacking. Above moth has dots along termen of fore and hindwing, and lots of fringe beyond as it is not worn. Have a look at images on 2 CD pages of Moths of Victoria Part 3, 2nd Ed Idaea sp(1). The Australian distribution map of the iNat specimens suggests the recent introduction theory. Compared to native Idaea sp iNat maps I have looked at.
the intensity of bands & amount of shading is variable between individuals. This can be seen in the iNat species 80 of which were IDed by Axel Kallies.
Looking at the photos of Idaea inquieta (ie. 'Idea sp. (1)') on the supporting disc to Moths of Victoria. I think the dark lines on the forewing on the basal half of the forewing meet the costa at a distinctly different angle than we see in this specimen. Also, while the sexes are apparently different in this respect, I do not see here the pale colour on the head between the antennae of the male of I. inquieta.