In Jan 2016 several of these were seen on the flowers of Lemon Beauty-Heads on Melbourne Airport land. Although it looks like a Grasshopper, the long antennae classify it with the crickets and Katydids.
Classification
from Australian Faunal Directory
Order Orthoptera - Grasshoppers, Crickets and Katydids, 1562 named species in Australia
Suborder Ensifera - Crickets and Katydids, 1093 species in Australia
Family Tettigoniidae - Katydids and long-horned grasshoppers, 394 species in Australia
Subfamily Conocephalinae - Long Horned Grasshoppers, 71 species in Australia
Genus ?
Species ?