A similar wasp was seen over a number of days in late April 2023 going into and out of a small hole in a dead tree, where she presumably had a nest.
Classification
from Australian Faunal Directory
Order Hymenoptera - Wasps, Ants, Bees and Sawflies, 12202 named species in Australia
Family Vespidae - Mud Wasps or Potter Wasps, 368 named species in Australia
Subfamily Eumeninae
Genus Pachycoelius
Species Pachycoelius carinatus