The New Zealand population grew by 214,000 people in the last seven years, census data released today shows.
The new Statistics New Zealand figures, based on the first census since 2006, showed that population growth had slowed compared to the previous census.
Government statistician Liz MacPherson said that on average the population grew by 31,000 people a year in the least seven years.
"This was slower growth than between 2001 and 2006, when the population grew by an average of about 58,000 per year."
The increase meant that a new electorate would be required in the next general election, in the North Island.
The total number of electorates would increase from 70 to 71, while the number of Maori electorates would stay at seven.
"Adding this new electorate means there will be one less list seat in the 120-seat parliament - excluding any overhang seats," Ms MacPherson said.
Each electorate must have roughly the same amount of constituents to ensure equal representation. After the changes, each electorate MP would represent nearly 60,000 New Zealanders.
New Zealand's general electoral population was now 4,242,048 - 2,867,110 in the North Island and 954,871 in the South Island.
The Maori electoral roll had a total of 420,990 people.
The population number was lower than New Zealand's estimated resident population, because it did not include overseas residents or people who did not complete the census.
Ms McPherson said that the new figures had been eagerly awaited by a huge number of people and organisations, in particular central and local government, iwi, business and community groups.
The population had grown by 6.6 per cent in the North Island, compared to 3.7 per cent in the South Island.
The largest growth was in Auckland. Its general electoral population now exceeded the electoral quota by 18 per cent - much more than the recommended quota of within 5 per cent.
The Hunua, Helensville and Selwyn electorates had also exceeded their electoral quota.
The most significant population declines had been in quake-damaged Christchurch. The Christchurch East electorate lost the largest amount of voters, followed by Port Hills, Christchurch central and the East Coast of the North Island.
Populations had swelled on the outer regions of Christchurch, in particular Selwyn, Wigram and Waimakariri.
- NZ population growing by 31,000 a year
- Total general electoral population now 4,242,048 - 214,000 higher than 2006
- One new North Island electorate will be created
- Number of South Island and Maori electorates will remain the same
- Largest population growth in Auckland
- Largest population fall in Christchurch