Breakvisual,
If you want to fly floats, contact Alligator Airways in Kununurra WA. Craig Muir is the owner and a very keen float pilot. The usual path is to do a season on the land planes and if you show a keeness, then you get onto the floats.
Once you have time on floats you are never out of work in Oz. Other operators can be found in Cairns and the Whitsundays as well as Tasmania. I'd contact them before spending any money as most will train you the way THEY want you do handle their aeroplanes. Consider getting a boat licence as well. Some states require it in Oz.
Good luck.