Note how it is hanging on by it's mandibles rather than it's legs - this is typical of the genus.
Classification
Species counts from Australian Faunal Directory
Order Hymenoptera - Wasps, Ants, Bees and Sawflies, 12202 named species in Australia
Family Megachilidae - Leaf-cutter Bees, Resin Bees and others, 169 named species in Australia
Genus Megachile
Species ?