It reminds me to a Braconid wasp (Braconidae), especially to the genus Atanycolus. Maybe you should look for Braconidae species in your area or, maybe, contact a Parasitica specialist.
Braconidae, subfamily Doryctinae near Doryctus sp. parasitoids of stem borers. All Doryctines are idiobiont ectoparasitoids of varios coleoptera larvae which live beneath bark or in wood like Cerambycidae, Buprestidae, Curculionidae and Bostrychidae. You must check which Coleoptera larva is boring your Eucalyptus trees.