IRD number: the key to being paid properly
The IRD number is your tax identity. Without one, employers must deduct tax at the highest non-declaration rate, and bank interest is over-taxed too. New arrivals apply online through Inland Revenue's "new arrival" process once they have an NZ bank account (or use the fully-functional account route), and numbers typically arrive within about two working days by text or email, up to ten by post. Do this in week one; it is free and everything financial depends on it.