It isn’t usually applicable to those intending to take up permanent residence in the country and applies mostly to contract workers and other short-term employees. Work visas are granted to foreigners only when no suitable New Zealand citizen or resident is available to do a job. Their issue isn’t based on a points system and each case is treated on its merits, taking into account the availability of local labour.
To obtain a work visa you must have a firm offer of a job in writing and apply to the NZIS, which can be done from abroad or within New Zealand (if, for example, you arrive as a visitor and then wish to work).
The visa fee is between around $150 and $290 (depending on where it’s issued) and isn’t refundable, even if your application is rejected! On arrival in New Zealand, you will be issued with a work permit, which applies only to one job for a specified period, usually a maximum of three years (but often for a much shorter period).