One of the North Island’s electorates will be abolished for the 2026 election. Andrew Geddis explains why the Act Party’s long-term parliamentary lifeline, the Auckland seat of Epsom, might be the unlucky loser.

Apparently you think that the Epsom electorate is going to be abolished at the 2026 election. Are you being needlessly provocative because you’re starved of attention?

Rude. And perhaps not entirely wrong. But also, I’m sort of serious. Shall I explain why? It does, I warn you, involve a trip through some electoral law with added maths.

Sigh. If you really must. Do please proceed.

I appreciate your enthusiasm. The government’s guardian of numbers, Stats NZ, has just released its calculation as to how many electorates Aotearoa NZ must have based on the 2023 census results. This process occurs every five years and using these most recent numbers, the North Island must lose one of its 49 general electorates.

Why is that? 

Because of three things. First of all, differential population growth between the South and North Islands. Basically, the South Island has grown more in relative population than has the North Island. Second, the South Island always gets 16 general electorate seats in parliament. That’s hard baked into our MMP electoral system in order to guarantee it a reasonable level of parliamentary representation. Third, all electorates must contain roughly the same number of people. Because the 16 South Island general electorates all now have more people in them due to its population growth, there must be one fewer North Island seat to maintain equality in the number of people in each electorate.

Gotcha. Adding relatively more people to the South Island compared to the North Island means more South Island representation relative to North Island representation. Is this a particularly new thing?

Well, it hasn’t happened since MMP was introduced. All electorate calculations since 1996 have added electorates in the North Island due to the North Island’s relative population growth historically outstripping the South Island’s. So, for instance, at the 2020 election the new electorate of Takanini was created in the far south of the Auckland urban area. 

This trend then has resulted in the number of electorate seats steadily increasing. At the first MMP election in 1996 there were 65 electorates (16 South Island general electorates, 44 North Island general electorates, five Māori electorates). At the 2023 election, this number had grown to 72 electorates (16 South Island general electorates, 49 North Island general electorates, seven Māori electorates). And that growth in the total number of electorates was expected to continue; the Independent Electoral Review (of which I was a member) predicted that by 2044 there would be 78 electorates. It will be interesting to see if the present reversal is but a blip in that long-term trend or represents an upending of those assumptions.

All right, then, a North Island electorate is going to have to go. Will the current 49 North Island general electorate MPs now have to go through some sort of Squid Game process to work out who is that unlucky loser?

That would be fun, but… no. The decision as to which electorate will get the chop lies in the hands of a bunch of folk on the Representation Commission. They are charged with now drawing the new electoral boundaries.

How are they going to do that?

By following a set of mandatory considerations in the Electoral Act. Chief among these is that every electorate must have the same number of people as the other electorates of its type, with a permitted deviation of only +/- 5%. In practice, the commission must chop up the North Island into 48 geographical areas that contain at least 66,381 people and at most 73,369 people. 

When putting the lines on the map that create these areas, the commission has to consider a bunch of other things: existing electorate boundaries; communities of interest; the infrastructure that links communities, such as main roads; topographic features such as mountains and rivers; and, the projected variations in electoral populations over the next five years.

If that’s the process, why, then, are you floating Epsom as being the unlucky electorate to disappear? 

Well, remember the binding requirement that each electorate has enough people in it (but not too many)? At the moment, there are 11 inner city Auckland electorates that fall below this minimum population level. They are the blue areas in the map below.

As such, every one of these electorates will have to have more people added into it. And look which electorate lies right in the middle of them all – Epsom. That electorate will need another 5,162 people in order to contain at least the minimum number of people inside its boundaries. And to contain the average number of people for North Island seats, it will need to add some 10,000 people. But it can only get these people by expanding its boundaries into other electorates that themselves have too few people in them and so would need to expand in size.

Epsom is also the second smallest of all North Island general electorates (with just 285 people more than the very smallest, Mt Albert). And its population isn’t predicted to get that much bigger over the next few years. As such, abolishing it as a stand-alone electorate and dividing its current population among the various surrounding seats could provide the people needed for them to meet their population requirements with perhaps the least amount of knock-on effects on all the other electorate boundaries.

But, Epsom really matters politically! It’s been the long-term parliamentary lifeline for the Act Party, so surely that means it ought to be kept?

Not for that reason it shouldn’t. The Representation Commission exists precisely to avoid drawing electorate boundaries for this sort of partisan purpose. The considerations in the Electoral Act are all it is able to look at, and none of these include “protecting the electoral interests of a current parliamentary party”.

Does that then mean Epsom is goneburger? Will David Seymour have to become a list-only MP in 2026?

Well, at this point I’m really only engaging in a bit of (informed) back-of-the-envelope speculation. Complicating matters is the fact that the electorates north and south of Auckland (in light brown in the above map) need to shed people to fit within the relevant population range. So if Epsom were to be abolished, the surrounding seats would have to accommodate not only its population, but also the excess population from these (rapidly growing) areas. The math might therefore lead to a different Auckland seat being dismembered to make this tricky balance work.

Then there is Wellington.

As this map shows, at present three of its seats have too few people in them. So they either will all need to expand in size to meet their minimum population requirements, or else one of them will have to go in order to provide the people for its neighbours. 

Fun and games ahead! How does it all get decided?

Basically, the Representation Commission draws up a set of “provisional boundaries” for all (now) 48 general electorates with the reasons why it is proposing them. These are made public, followed by an objection period of at least one month where anyone who thinks the commission has got it wrong can tell it why. Once this objection period ends, there is then a counter-objection period of at least two weeks, where people can tell the commission why the objections it has received are wrong. 

After having received all these objections and counter-objections, the commission considers what it wants to do and releases its final boundary determination. This determination may accept the objections, or it may ignore them, or it may do something else entirely. And once that final boundary determination is made, then that is it in terms of the shape of the electorates for both the 2026 and 2029 elections.

Any final passive-aggressive drive-by remark before you’re done?

Well, if central Auckland and Wellington had permitted greater housing densification, the growth in those area’s populations perhaps wouldn’t have fallen behind the rest of the North Island’s in relative terms. And if that were so, they wouldn’t now be looking at perhaps losing local electorate representation in parliament. I guess heritage values carry their own unexpected costs…