It would be pretty tight , wouldn't it ? There would be only 11 hours to allow for ground time in MEL , MEL-AKL sector , ground time in AKL , AKL-MEL sector and ground time in MEL again . Probably doable if nothing goes wrong , but not a lot of margin for delays . If you could do the turnarounds in 60 minutes it might be ok , but isn't 90 more usual ( don't forget that all transit pax for AKL would have to disembark at MEL with all their hand luggage , go through security screening and then re-board - although admittedly I would expect the numbers of transit pax to be quite low )