Over the past few years, both Y and C saver award seats for around Christmas/new year have opened up a few weeks beforehand - however realistically there's no way I suggest relying on that occurring. The combination of Christmas, New Year and it being summer in Australia makes that a very busy time, and it's unusual for flights to go out without being at least almost full.

And of course, it's not a good time to be having to pay for flights either - they aren't exactly cheap...