I don't know of an Australian manufacturer of tripods. I would recommend Tasmanian Oak as a suitable local wood. It is plantation grown, has good strength to weight and is readily available in pre-dressed lengths that can be cut/drilled easily.
I believe Tassie Oak is a commercial name for what is really a native Ash.
Jarrah is a nice darker coloured native wood, however it is heavy and expensive and not necessarily better for this application.
Commercial wooden tripods such as Berlebach (German) use European Ash.
http://www.berlebach.de/?bereich=firma&sprache=english