Males have a rounded head.
In the described male and female, the abdomen is mottled greyish brown and beige. The male has a dark reddish-brown head and thorax; these are brown in the female.
Male Austrarchaea cunninghami have a brush of accessory hairs on the front of the basal cheliceral segment; the described female lacks this brush. Both described sexes have three pairs of small dorsal abdominal humps. The described male and female measured 2.82 and 3.54 mm in total length respectively.
The 2011 revision combined morphology with DNA. Three specimens, including a female and juveniles, had four diagnostic nucleotide differences across the COI and COII regions relative to the other taxa genotyped in that study. DNA comparisons supplied additional identification evidence for juveniles, whose adult reproductive structures are unavailable.
An extinction-risk assessment has not been added yet.
At Main Range National Park, where this spider occurs, the 2013 management statement extended in 2024 describes boundary fencing to exclude cattle from neighbouring grazing land and cooperation with neighbours on fire management. It records continuing fencing and ridge-top burning as parts of regional park management intended to limit wildfire impacts.