An adult is shown here.
The larva feed on plants in the family Polygonaceae, mainly various species of Dock.
Classification
from Australian Faunal Directory
Order Hymenoptera - Wasps, Ants, Bees and Sawflies, 12202 named species in Australia
Superfamily Tenthredinoidea - Sawflies, 161 named species in Australia
Family Pergidae - typical Sawflies, 140 named species in Australia
Genus Lophyrotoma
Species Lophyrotoma analis - Dock Sawfly