Gympie Bush is Dendrocnide morioides. There are about 6 species of Dendrocnide in Australia and another 30-40 in other parts of the world. As far as I know they are all stingers but D.morioides is the worst of the Australian group.
It is a medium sized shrub with large oval shaped leaves. It lives in rainforests all down the Queensland Coast and into north-eastern New South Wales. The plant has stinging hairs on the stems and leaves and the sting can be excruciating for several days and then may reoccur over a period of months. (see link)