I find it hard to believe that VANZ truly is cheaper anymore than VAA on trans-tasman and island flying.
Running a separate AOC down here with separate management and doubling up on everything. Adding to this is the Kiwi dollar strengthening, the contracts crew are on strengthening, inefficient trips with paxing sectors across the ditch both ways, returns out of Australia (with associated hotel and transport costs). Then there is the issue about mid duty sickness/fatigue with either delays, cancellations or VAA stepping in.
Yes at present their flight and duty limits are less restrictive, but Air NZ certainly don't do those returns. VANZ has already lost island flights to VAA with more to come. Business class is on the way so that rules out the excuse why some routes maybe onshored back to Aussie.
I'm afraid to say it, but it's just a matter of time before the true picture is realised and the operation is packed up and operated more efficiently by VAA.