The boat trips out into the harbour are splendid - take a ferry to an island, or just do the round trip.
Try and get someone to show you a morpork, or at least hear one. We had one under our window when jetlagged. It's an owl, and yes, the word was used to go with Ankh.
Kiwis are fun, too, but you'll probably need a nature park or something for them.Much smaller than I thought.

If you get to drive, try and flatten a possum - the locals will thank you. I have my possum-fur Kiwi on my desk as I write.

And try and meet up with Little Robyn and Mitch - she's a fund of knowledge, folkie, & NZ / Maori-wise.

Flights the other way round(we did Heathrow - LA - Auckland) were one stop, 10 hours airtime the 1st half, 11 hours the second. If I ever did it again, I'd take a day or so in the middle. It was too much in one go.

Paws