I'm not convinced that this is Paropsisterna beata. Due to size and that it was on Acacia, I'm more inclined towards Peltoschema sp. but would like Kim's opion on this @KimberiRP
An interesting colour variation of this species, which usually has a lot more yellow in its markings. Here (on ALA) is an even darker variation - just two tiny flecks of yellow on the elytra: https://biocache.ala.org.au/occurrences/c64700bc-52f0-4d2b-a115-0a0f31d90a3a