A worn example. While most records of this suggested species are from Tasmania: https://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:9c14c72b-7fae-44f1-ba6f-c8cd1120a2ec#overview the ALA makes it clear the species also occurs on thr southern Australian mainland as well (as does LBH also). Bold Systems 4 shows records from southern eastern NSW. Moths in the ACT says ' There is at least one other similar Synorea species (i.e. similar to S. eubolaria and E. hemeropa) present in the ACT' without naming the species involved. This is a new species record for the ACT if confirmed.
I halmaea is recorded widely in Vic (source Moths Of Vic Pt3 CD) Dist almost bottom 1/2 of Vic including NE border so not far from you. Also gives ACT in Aust distribution which I assume means Peter has seen specimens from ACT in ANIC or MusofVic (also NT, Qld, NSW as well as Tas)