Bold Systems 4 shows at least 6 records which are annotated saying they were collected in the ACT, see here: http://www.boldsystems.org/index.php/Taxbrowser_Taxonpage?searchMenu=taxonomy&query=Phyllonorycter+messaniella&taxon=Phyllonorycter+messaniella
But should it be shown as ‘exotic’? (Not ‘local native’). Atlas of living Australia seems to show that it is native to Europe, ‘The European oak leaf-miner or Zeller's midget (Phyllonorycter messaniella) is a moth of the family Gracillariidae. It is found in Europe south of the line running from Ireland, through Great Britain, Denmark to Ukraine. It is also found in Macaronesia. It is an introduced species in New Zealand and Australia.’