Registration is free, but you need to be a Kiwi or at least in New Zealand to register with yas.nz.
After you register you will be sent a validation link via email.
* If you do not have an email address in the '.nz' namespace you need to use a New Zealand based mobile number to validate your account in addition to the email link.
The number format includes the '+64' so if your local number is 027 212 3123 then you enter '+64272123123'
After your first login you will be prompted to validate your mobile number and a short code will be sent via TxT to the number you provide.