I don't know much about the pay, but can tell you a few things.
The time you can expect to be an S/O is anywhere from 7 to 15 years. Time to command can be 20+ years. The job is very stable, I can't think of the last time they made redundancies. The company is very well positioned to the future with a nimble management team, good alliances and a modern fleet mix.
They have made it known the majority of new hires they want to take on will come from the Air New Zealand Link companies, with very few from outside those. In fact I know of someone with 3000 hours on A320s, who was told to go join Mt Cook or Air Nelson for three or four years before he'd be given an interview.
There is a slim chance of getting on the 737, but may only be two or four positions at the most. You will not get direct entry to the A320, ever. Expect to be with the company about 10 years before you get the chance on the A320.
Yes people won't be happy with how they recruit, but at the end of the day it is their train set and they can pretty much dictate how people get to use it.