Hi,
I traveled to NZ a couple of times and fished around Rotorua. It is really an awesome place. Because of my limited time there, I got myself a guide from Rod and Reel in Auckland. The guide put my wife and I onto many good fish.
Since you got some time there, you would have many opportunity to explore. The Kiwis are really helpful and friendly, unless you are wearing a Gold and Green rugby jersey. 😛 There isn’t any dangerous snake or bear but just be a little more sensitive when the All Blacks lose. Rugby is a religion there *some say that it is an understatement” …. 😛
I would be bringing a friend to North Island in March next year. It would be his 1st time fly fishing for trout. Hopefully I would be able to make the trip fruitful for him too.
Cheers!