I toured the North Island for 16 days in February this year. I hired a bike starting in Auckland and only toured around North island. Great roads, helpful people and stunning places. A large bike is not necessary (I hired a Suzuki DL650). I took camping gear as from previous driving experience in NZ, I learned the camping areas are good and you need to be flexible. I also used cabins when rain was about but used to stay a couple of days and do local rides.

In Feb/Mar 2017 I am shipping a bike to Christchurch to tour the South Island. I will again be using camp sites/cabins/ B&B or motel depending on rainfall. I will head clockwise or anticlockwise depending on the weather however I would prefer to tour the southern part of the island before it starts to get too cold. It was very rainy in South Is in Feb/Mar this year I noted when monitoring the weather.

The school children go back to school in Feb and so accommodation can be a little easier but you can get caught out by the number of (very) popular events that are on that soak up available accommodation.

Getting your own bike to NZ can require a bit of work but I wanted to experience that also (as well as spending more time in NZ. From Australia the break even point for hiring vs shipping is about 11 days.

Happy to supply some info from my experience of NZ if you want to PM me. The experience is very positive (one reason for going back!)

Mal