The Maori Party's Te Ururoa Flavell is upset about the proposed electorate boundaries, saying that the proposed Maori electorates are too big. He's right - they are, geographically speaking. But that's because electorate boundaries are not determined by geographical size, but by population. And on that measure, Maori electorates are pretty the same size as general ones (60,141 people vs 59,679 for the South Island quota - the difference is due to rounding error, and far less than than +/- 5% permitted under the law).
Maori make up ~15% of the population, and only half of them go on the Maori roll. Which means that a Maori electorate, by definition, is going to be on average the size of 13 general ones (with the actual ratio varying with the distribution of the Maori electoral population - more in the South Island, less in Northland and the Bay of Plenty). That's just the cost of having electorates for a subset of the population.
As for how to "fix" it, Flavell
electoral law guarantees there will be at least 16 general electorates in the South Island so each one won't be too big, and that approach should apply to Maori electorates.
But regardless of the number of South Island Maori electorates chosen, this can only lead to one result: massive political over-representation of Maori. Which is simply a non-starter in a democracy committed to one person, one vote (and its corollary, one vote, one value).
What we can do is resource MPs representing such electorates adequately to allow them to maintain a presence (and interact with constituents) across their electorate. there's already some recognition for this in the Parliamentary expenses framework - MPs representing "large electorates" (anything bigger than 12,500 square kilometres) gain increased support funding and staff entitlements. But its clearly not enough to deal with the distributed population of the large Maori electorates. Something needs to be done here to ensure that Maori voters get the access to representation they deserve (and which is enjoyed by everybody else).