I am not Kiwi so my suggestiones might not be the best but I just finished a 10 week run around in New Zealand which I did 12 k kms.

Im afraid the weather can be a bit harsh from now one. I had a bit of bad weather the last week there on the northern island.

Well - from Auckland you could ride down to Rotorua. From Rotorua you can either take R 38 over the moutain range to Wairoa - this route has a fair bit of gravel and is very winding at stretches.
Or you could ride to Opotiki and take R2 over the same mountain range to Gisbourne. This is a nice and winding ride through very nice scenery and on paved road.
From Gisbourne you could take the inland road toad to Wairoa - The Tiniroto rd - a very winding road through remote and beautiful scenery.

Then you could ride down to Napier and take the Napier - Taihape rd - again a very winding road through remote and beautiful areas - paved all the way.

Then Taihape to Taumarunui and Taumarunui is the one start/end of "The Forgotten State Highway" - one of the more famous roads on the north island. Again very winding and through some amazing and wild scenery. Just a very very few kms is gravel.

From Stratford and down to Wellington will be pretty ordinary though.

Hopefully some Kiwis will come up with corrections if I misspelled some names and for improvements of my road suggestions. Just wanted to share some of the roads I did and enjoyed.

Have a great trip!

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