"Might be" is the operative word. We will see if the non-left parties can actually be joined together into a fuctional majority coalition. There are several rough edges to this. One of these is the potential conflict between the Maori Party, which wants special concessions, and some or all of the other parties.
NZ First actually embraces the idea of some special concessions for the aboriginal people of their country.
The United Future Party is a Christian centrist party. They want a decent society in which there is a safety net for the poor and disadvantaged.
ACT may look at this pragmatically: It's better to have some special concessions for a relatively small fraction of the population if this means that you can cut spending and taxes for the majority (even though not by as much if you didn't have to make any special concessions).
National, being a center-right party, and incorporating all the sentiments I just described, would be happy with any deal to which NZ First, United and ACT agree.
Plus, the Maori people really are badly off. Maybe one-half of them are in jail. Unemployment and dependency abound. They suffer the way people suffer in some of our worst inner cities and Indian reservations. If conservatives were to structure the special programs for them, as opposed to the liberals being in charge, maybe things could be better.
Great for New Zealand! Maybe a lot of changes coming, and hopefully most for the better.
(But that's no way to run an election. How come the dead didn't vote? If you want to copy American elections, you should have rosters from the cemetaries, already prepared. That's how they do it in Chicago. . . )
There's a few things to note on the Maori people before comparing them to American Indians living on reservations. Firstly is that New Zealand is an integrated society and has been for generations. There are no full-blooded Maori people.
You might also want to do some research before saying half a population is in jail. 7000 prisioners total (as of April)
[source http://www.stuff.co.nz/stuff/0,2106,3263458a11,00.html]
There's a reference elsewhere which said 70% of the prision population have Maori ethnicity, so about 5,000 total.
NZ 2001 Census results
http://www.stats.govt.nz/NR/rdonlyres/E717D06C-0687-4BC7-BD05-D8AEF8D39E3A/0/Table1.xls
600000 people of Maori descent total.
So rouchly 0.83% of Maori are in prison. Higher than those without any Maori ethnicity, but MUCH less than the 50% you quote.