There are similar looking moths on the ALA, see postings by Graeme Cocks:- https://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:e27d5739-e6b7-4d41-bc88-26d2c893d762#gallery
This record matches the type photo of Labdia oxysema, and that species seems to be the most common of the small black and white Labdia. The records under L. oxysema on BOLD are a different species.
Hi Katarina, following Glenn's amazing identification of this moth, I have written a webpage around your beautiful photos at http://lepidoptera.butterflyhouse.com.au/cosm/oxysema.html Thanks Katarina and Glenn, Don