Well robair,
Have YOU asked them to do anything for you? If you havent joined them then of course they are not going to help you, dunno about aussie unions but the NZALPA is making a effort to help GA pilots, and considering the income they receive from them probably putting more resourses per dollar received into GA than the larger airlines in NZ.
As a GA pilot I never had less than 100% support from NZ ALPA whenever I asked for it.
Perhaps if you asked the aussie one may be persuded to do the same?
Dont know till you try.