I think this was a Green-bellied Huntsman. I was not able to get a good shot as the spider was high up in a tree at Aranda Bushland Nature Reserve. The spider was large, possibly 10-15 cm across. I had first noticed the reflection from its eyes, thinking it was a small mammal given the distance I noted the reflection and where it was in the tree. This spider was very obvious on the branch once we shone the torch on it. There is a line of ants behind it in the photograph but they look too small for the spider to consume.