For people who must pay, the cost is "$3,100 for the first or only person in the room (whether that is an adult or a child) with $950 for each additional adult and $475 for each additional child (3-17 years old, inclusive) sharing that room, all GST inclusive." (All costs are New Zealand dollars, of course.)
There are exemptions for New Zealand citizens, if they are returning for a period of at least 90 days and left before August 11, 2020.
The charges are different for "critical workers" whose fees are paid by their employers; if you fall into such a category, you should read the relevant info.
All this is, of course, subject to change on short notice.