The chair of the Electoral Boundaries Commission, Judge Craig Thompson unveils the provisional 2020 boundaries yesterday.

The release yesterday of the new provisional electoral boundaries sees the number of list seats in Parliament reduced by one more.

What was originally proposed to be 60 list seats has now shrunk to 48.

It has been an inexorable process which begun in 199 when MMP was introduced.

It is a consequence of the original decision to hold the number of South Island Island seats at 16.

The population of the South Island is then divided by 16 to give the average size to be used to define North Island seats.

But the North Island population is growing faster than the South Island  — 28 per cent versus 22 per cent over the past 17 years.

The result is that the number of North Island seats is constantly having to go up and that is achieved by taking one seat out of the list and turning it into an electorate seat.

Thus yesterday the new boundaries show a new seat in south Auckland between Manurewa and Papakura which will be called “Flatbush”.

National Party officials say they believe it will be a marginal seat which could bring an electoral contest to south Auckland for the first time in years.

But the bigger question is how much longer the Electoral Boundaries Commission can go on “raiding” the list to preserve the size of North Island seats which is defined by the slower-growing South Island.


Judge Craig Thompson admitted yesterday it was a fair question.

But, he said, it was a question for Parliament, not the Commission.

Ultimately, if the trend continues, there will be difficulty maintaining the proportionality of Parliament.

This was a point made as far back as 2002 by the Chair of the 1986 Royal Commission into the Electoral System.

“MMP  will not operate satisfactorily if there are insufficient list MPs to maintain proportionality,” he said in an article in a law journal.

The “safety valve’ for Parliament is the so-called “overhang” which means that additional seats can be allocated to parties beyond 120 if it is necessary to maintain proportionality.

The consequence of this is that the electorate seats are becoming more important; not in terms of who forms the Government but in terms of who gets into Parliament.

One of the factors that led to Labour’s decision to replace Andrew Little with Jacinda Ardern as the leader in the run-up to the last election was the imminent prospect for some Labour list MPs losing their seat because Labour was polling too low.

Thus a safe electorate seat is a guaranteed ticket to Parliament; anything other than a top list position is not.

At one point in 2017 when Labour was polling in the low twenties, it looked possible that even senior MPs standing on the list like Trevor Mallard and David Parker could lose their seats.

The changes announced yesterday primarily affect Auckland and the north. But there are other more subtle changes right around the country.

Seat by seat

The Maori Seats

No significant changes.