What plant was it feeding on? This photo is only consistent with photos of the larvae of P. tristifica, out of the photos of larvae of 13 species that we have of Agaristinae, but we have no photos of the larvae of the other 31 Australian Agaristinae species. I could be one of those! Can you rear it in protective custody to an adult moth for confirmation please?
Hi Don, sorry don't know the name of the plant, have added an extra pic showing as much of the plant as possible in a photo, hope this helps. We are unable to reach the caterpillar as the plant it was on is on the edge of the water of the pond which has a locked fence all around it.
Thanks Tapirlord for already adding the plant information. I was just about to add the plant info as just got the name of the plant from Rainer Rehwinkel who kindly informed me it is on a native willowherb, Epilobium sp. Thanks Don also for your help.