Hi Jan,
Theischinger, G & Hawking, J. (2006) as mentioned by Stephen Ambrose is the only field guide that I know of and very useful although I tend to find things by thumbing through the pages of a well-worn copy.
If you have photos and an accurate location the inaturalist website https://www.inaturalist.org/ is an international citizen science website with a large pool of identifiers including in Australia. I’ve found this useful to get an id for invertebrates, particularly moths, butterflies, dragonflies and grasshoppers. Some of the identifiers are leading experts in their field. Data entered into inaturalist also feeds into Atlas of Living Australia with the added bonus of increased accuracy of identification. IDs often come back within a couple of days.
Cheers,
Euan
