Yes,
We were in Australia two years ago, and our Etrex Legend worked. You will need to go to satellite menu, then click over to pop up menu and scroll to new location, then move the curser to use the map. Use the arrow to find your way to Australia. It took us a bit to figure this out, so hope this helps. Don't know if you have ever been there or if you are from there, but it is awesome. We did not purchase any Australian mapping, and it was fine for us, as we were just visiting.
Have fun
Dave and Cindy