Just another way of screwing down wide-body salaries if you ask me.
framer, it's more about saving accomodation and allowances. Because the day's work for an aircraft starts out of AKL (for example) an NZ domiciled crew can fly the aircraft to an Oz east coast port and return (approx 6 stick hours) and then go home. Another crew then takes the aircraft to Oz and back arriving AKL late evening. The aircraft then has some hours on the ground for maintenance. All up, it's taken two crews to operate the aircraft all day for approx 12 stick hours and there has been no need for accomodation. If the crews are Oz based, then the crewing costs go up significantly. Air NZ has had this advantage over QF for many years so QF is looking at ways to be competitive on what a very price sensitive route.
The schedules are effectively locked in by times that businessmen want to travel, so there is no way to adjust the flight times so that Oz based crews don't require accomodation in NZ.