In the United Kingdom authorised persons include:
* Notary Publics
* Justice of the Peace
* Solicitors
* Commissioner for Declarations.
As far as NZIS are concerned it is anyone who can lawfully certify documents in the country that you are in, so different countries have different rules. I am sure that I have seen somewhere that medical doctors can certify documents?
Would agree with others, get all your documents together in one go, and if possible take the copies ready for them to just certify, makes it easier for them and they won't charge you for making copies.
Ian