I came across this reference on a New Zealand government webpage:

You may already be a New Zealand citizen if you were:

* Born in New Zealand (including the Cook Islands, Niue, Tokelau, or the Ross Dependency) prior to 1 January 2006.
* Born in New Zealand (including the Cook Islands, Niue, Tokelau, or the Ross Dependency) from 1 January 2006 and at least one of your parents was a New Zealand citizen or entitled to be in New Zealand indefinitely at the time of your birth. (For further information see the Changes to Citizenship by Birth in New Zealand from 2006 Frequently Asked Questions).
* Legally adopted by a New Zealand citizen parent (if you were adopted overseas we need to check that their adoption laws are similar to ours).
* A British subject resident in New Zealand during all of 1948.
* Granted New Zealand citizenship.
* Born overseas to a New Zealand citizen parent.

I am an American born US citizen. I was adopted by my step-father (as part of a weird child custody issue) as a child, who is a native born New Zealand citizen. Am I a New Zealand citizen, even though I have never had residency there?