If you meet the requirements mentioned here
http://www.immigration.govt.nz/migra...am.htm#student, under 'Your partner holds a New Zealand student visa', your partner can get the partner-sponsored temporary work visa mentioned on that page. Check first that the course is approved for grant of a NZ student visa, because someone recently posted on the forum that he found he had signed up for something that wasn't eligible. If your partner is applying for the partner-sponsored temporary work visa, your children can be granted a student visa if over five years old, or a visitor's visa to match the parents' for length if under five years old. You can apply for all the visas at the same time, linking them with a covering letter, and INZ will work everything as one case, supplying what you do not know at first, like your visa number, as it becomes available.