The NZ Health Service is not an insurance. Aside from that, you're right - with a work visa for a minimum of 24 months, your wife will be entitled to treatment on the same basis as NZ nationals and residents. And everyone can use ACC.
http://www.dol.govt.nz/immigration/k...base/item/1342 If your wife gains a job offer which will qualify her to apply for a visa, you can apply at the same time for a partner-sponsored temporary work visa
http://www.immigration.govt.nz/migra...milystream.htm, to run for the same length of time as her visa, so you will have the same entitlement. (You apply at the same time, linking the applications with a covering letter, and the CO will work it all as one case, supplying details such as her visa number, which you would not know at the beginning, as they become available.)