Yeah, I am comparing the same direction - it is coming up in the same search result! Just looked it up again and here is what it is saying:
Philippine Airlines
19:15 AKL 21:55 CNS 4h 40m
Air New Zealand
09:15 AKL 12:50 CNS 5h 35m
If it is indeed so long, it is quite painful that Air New Zealand don't offer business or premium economy! Not the easiest for really tall people to fit in a small seat.