Maybe not. New Zealand Herald reports:
The influence that the Maori Party may exert in the formation of the next Government will strengthen the argument of those who feel that, under MMP, small-party tails are wagging large-party dogs. But that does not, of itself, argue for the abolition of the Maori seats. NZ First, Act, United Future and the Progressives have all, at different times and to different extents, exerted influence disproportionate to their mandate. That is MMP.
The leading party may put MMP to a referendum -- if it holds enough seats to do so.