I just began reading "Australian Medicinal Plants" by Lassak & McCarthy today, you may find the following quote interesting:-
The assumption that the Tasmanian Aborigines had no knowledge of herbal medicine, except for the use of the 'pigface', a species of Carpobrotus as a purgative is unlikely to be entirely correct and may simply reflect our lack of knowledge of them owing to their early extinction
The book itself will probobly suggest several plant medicines native to Tasmania, however, for any region all we really have now is fragmented and often unreliable sources that we must some how try to reconstruct.
I've just written a paper called 'Tools of the vegetable kingdom' focused mostly on plant materials used in making tools but also covering some aspects of drugs, medicines and poisons as applicable to subsistance as well as some plant processing such as fermentation, leaching and salt leaching as a tool in food production and have suffered from a lack of reliable source material. (it should be in print and available from your state library by Xmas)
You may be able to derive some good info from the following books for your locality:
Bush Medicine - Tim Low
Aboriginal Plant Collectors - Philip A Clarke
Aboriginal People and their Plants - Philip A Clarke
Their are others by Peter Latz which are always high on my resource list, however I havent sighted these in some years and can't recall if they had much southern info in them as he specializes in Arid regions.
sorry to disappoint
one shot, two shot, three shot, floor