A domain transfer authorisation, or UDAI (Unique Domain Authentication Identifier) code is the key to your domain name.
An Authorisation Code is 16 characters in length and consists only of alphanumeric characters needed to transfer a .nz domain name from one domain name provider (registrar) to another. The code for your domain name must be provided to you promptly by your current registrar whenever you request it.
Authorisation Codes can be used only once.
An Authorisation Code is valid for 30 days from the date of its generation.
If you are asked to provide a UDAI to anybody for any other purpose than changing the registrar for your domain name then you should query this request.