Does it matter that it is not a university?
For the visa, no. Immigration New Zealand lists the qualifying qualifications as “a degree level 7 or higher qualification”, naming the level 8 postgraduate diploma, the level 9 master’s and the level 10 doctorate. There is no provider-type restriction, and with a level 7 or higher degree you can “do any work in any job, anywhere in New Zealand”. You must have studied full time in New Zealand for at least 30 weeks, and you can hold the visa only once.
For the money, it matters a great deal. Wintec publishes NZ$24,600 a year for its Master of Applied Management and Unitec about NZ$30,415 per 120 credits for its computing master’s, where the University of Auckland publishes NZ$55,484.50 for 120 points of engineering. That is not a small difference over an eighteen month programme.
Two things do genuinely differ. Rankings and research reputation sit with the universities, which matters for some employers and not others. And engineering is a university route: the institutes of technology do not teach an engineering master’s, and several Green List engineering roles ask for an accredited undergraduate engineering degree that no master’s supplies.