Idiodes siculoides has a vague dark spot on the underside, so this ID is doubtful, but Arhodia lasiocamparia has much more obvious underside markings which this specimen certainly does not have.
I suggest this species is more likely to be Arhodia than I. siculoides. After referring to the Moths of Victoria (MoV) images for both species I think the forewing tip shape is not what I would expect for I. siculoides and it lacks the under hindwing spot of that species. I think the visible underwing view is consistent with the under hindwing pattern of Arhodia spp. given that the characteristic under forewing blotch is obscured by the overlapping hindwing in the third image.