E4.75 contains information pertaining to the obligation to inform INZ of all relevant facts, including changed circumstances. To summarize: ou are obliged to inform INZ of any material change of circumstances that occurs after the application is made, including if that change may affect a decision to grant entry permission in reliance on the visa for which the application is made. Failure to do so can have severe consequences. Note too, that if the visa is already granted, a material change in circumstances may lead to the refusal of entry permission at the border (see
Y4.25 and
Y4.35).
Should the change of circumstances occur while the applicant is in New Zealand, a different temporary entry class visa may be applied for (see
E3.30 and
E3.35).
EDIT: A related personal experience of my own. While I was originally in New Zealand on a Visitor Visa (scoping things out on a "look, see, decide" trip), I received a firm job offer. Within a few days of that, I had gotten my medical done and lodged the application for the appropriate Work Visa, which was subsequently approved less than 2 weeks later.