Wasps with this appearance are fairly commonly seen in the park.
Classification
from Australian Faunal Directory
Order Hymenoptera - Wasps, Ants, Bees and Sawflies, 12202 named species in Australia
Family Ichneumonidae - parasitic wasps, 472 named species in Australia
Subfamily Tryphoninae - 16 named species in Australia
Genus Netelia - 11 species in Australia
Species ?