There will be a new electorate at the 2020 general election resulting in one fewer list seats in Parliament than at the 2017 election.
Stats NZ released new information on Monday about electoral populations which is used by the Representation Commission to determine the general and Māori electorate boundaries.
The number of electorates will increase from 71 to 72 at the next general election, with a new electorate to be created in the North Island.
It means that in a 120-seat Parliament - excluding any overhang seats - a total of 72 electorates will result in 48 list seats being allocated, one less than in the 2017 election.
There have been seven Māori electorates in each of 2008, 2011, 2014, and 2017 general elections, and this will remain the same in 2020.
Regularly adjusting the electorate boundaries makes sure each electorate has about the same number of people. This gives all New Zealanders equal representation in Parliament.
Each electorate must not exceed 5 percent or be below 5 percent of the set quota, which is 64,899 for the North Island and 65,458 for the South Island.
There will be changes to roughly a third of electorates that are out of the tolerance zone and need to be brought either up or down.
A Stats NZ spokesperson said the new electorate boundaries could be announced in April next year.
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In 2014, two new electorates were announced: Upper Harbour and Kelston in west Auckland, and Waitakere was dissolved - so it was a net increase of one electorate.
The 2018 Census found that the population of New Zealand is 4,699,755, and relatively high net migration suggests the population will reach 5 million in the "near future".
Auckland is home to one-third of New Zealand's population topping 1.5 million.
Christchurch made a comeback following the 2011 earthquakes. The city's population of 369,469 was up from 341,469 in 2013.
New Zealand’s population has grown by 458,000 since the last census, an increase of 10.8 percent. Stats NZ say it is likely New Zealand will reach 5 million by 2020.
The European ethnic group is still New Zealand's largest by a "significant margin", but they made a smaller proportion of the population - 70.2 percent - than in 2013 when they made up 74 percent.
The next largest ethnic group is Māori representing 16.5 percent, followed by the Asian ethnic group making up 15.1 percent of the population.
The 2018 Census combined census forms with administrative data to create the information.
It follows the resignation last month of the chief executive of Stats NZ, Liz MacPherson, after a review of the 2018 Census identified shortfalls in the 'digital first' approach.
MacPherson conceded the official data agency had been "too optimistic, placed too much emphasis on the online census, and did not have robust contingency plans".
The review also found that just 68.2 percent of Māori participated in the 2018 Census, down from 88.5 percent of respondents in 2013. The response rate from Pasikifa people was just 65.1 percent down from 88.3 percent.
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A panel released the first of two independent reports on Monday on the quality of data from the 2018 Census, with the second to be published in December.
It found that one in six New Zealanders did not complete the census, "largely due to operational failures that made it difficult for them to participate".
The panel has endorsed Stats NZ's decision not to publish iwi data as official statistics due to insufficient data quality, and noted that Stats NZ have not met their Treaty obligations to Māori.
"With regard to ethnicity, comparison with data prior to 2018 should be undertaken with extreme caution, particularly for Māori and Pacific ethnic groups," the panel said.
It also said household and families data will be "generally of low quality and will not enable comparisons with 2013".
However, the panel found that the use of administrative and 2013 Census data has improved the quality of results.
This was especially the case for Māori and Pacific ethnic groups in the population.