but a recipe i have calls for cake flour, what would it be called here in Oz?
Contrary to some of the links expressed in this thread, Australia does have cake flour
It's simply finely ground flour with a very low gluten content, same as the American version. Another name for it is soft flour. The British call it extra fine. But it's the same thing. You just have to check the packet for the gluten/protein content before you buy it. This value is expressed in percentages and a lot will say "for cakes and pastries".
The name cake flour (which is also found in Australian recipes) is specified to prevent people from using bread (strong/hard) or all purpose/plain flour which has a higher gluten/protein content and is not suitable for cake making (although it won't kill you to use it...just won't give you the same result).