On trans Tasman (NZ<----> Au) on Air NZ you can pay extra $30 for a exit row. Expect will be the same on NZ long haul, but more $$. If that can be done with an airmiles ticket is another matter. But on an ordinary cash fare have the chance to purchase exit row at any time on line.
If first going to an Au airport not served by AC (BNE-SYD-MEL) then via AKL is viable option. The SYD international <---> domestic shuffle is best avoided if possible.