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National Population Estimates: At 30 June 2015
Embargoed until 10:45am  –  14 August 2015
Data quality

This section contains information that does not change between releases.

Base population

The estimated resident population at 30 June 2013 forms the base population for deriving post-censal population estimates.

The estimated resident population of New Zealand at 30 June 2013 (4.442 million) was derived from the 2013 census usually resident population count at 5 March 2013 (4.242 million), with adjustments for:

  • residents missed or counted more than once by the census (net census undercount) (+104,200)
  • residents temporarily overseas on census night (+81,700)
  • births, deaths, and net migration between census night and 30 June 2013 (+9,300) 
  • reconciliation with demographic estimates at ages 0–9 years (+4,800).

Quarterly national population estimates from September 2013 onwards are derived by updating the estimated resident population at 30 June 2013 for births, deaths, and net migration during the following period. 

Accuracy of the data

Official national population estimates give the best available measure of how many people usually live in New Zealand. We produce national population estimates using a component methodology, where a base population is updated for the components of population change (births, deaths, and international migration).

All population estimates have some uncertainty around them. Generally, the uncertainty associated with population estimates increases as the estimates move further away from the base (starting point). Uncertainty also increases as population estimates are disaggregated (eg by age or subnationally).

The uncertainty is the net combined effect of:

  • uncertainty in the census-based estimates of the population at 30 June of the current or previous census year, including uncertainty in the census counts (eg from respondent errors or census processing) and uncertainty in the adjustments (eg for net census undercount and residents temporarily overseas)
  • uncertainty in the estimates of any of the components of population change (births, deaths, and migration) since the previous census.

It is not possible to verify the ongoing accuracy of current national population estimates, as no other independent or authoritative measure of the resident population exists. It is possible to derive retrospective measures of accuracy following the periodic Census of Population and Dwellings.

Following the 2013 Census, we revised national population estimates at 30 June 2013 down by 29,000 (0.7 percent relative to the revised estimate).

International migration estimates

International migration statistics are based on electronic arrival and departure records supplied to Statistics NZ for each international passenger. All arrivals and departures are processed so they can be allocated to one of three passenger types: overseas visitors, New Zealand-resident travellers, and permanent and long-term migrants. The net number of permanent and long-term migrants provides the estimate of international migration that we use in deriving the national population estimates.

Uncertainty arises due to changes in passenger intentions; a person may change their intentions after their arrival or departure, which may mean the recorded passenger type becomes incorrect.
We do not currently revise published statistics to adjust for such changes.

Birth and death estimates

There is some uncertainty associated with birth and death data. We use birth and death registrations to estimate the number of births and deaths that occurred during each quarter. Not all births and deaths that occur in a quarter are registered by the end of the quarter, and this delay in registration is taken into account when estimating the number of births and deaths in the current quarter.

Provisional and final estimates

We publish provisional national population estimates in quarterly table updates about six weeks after the end of the reference quarter. An annual information and media release accompanies the June quarter release in mid-August.

Final national population estimates are published in quarterly table updates about five months after the end of the reference quarter. We derive these final estimates when an extra quarter of births and deaths data is available. Changes between the provisional and final estimates are most apparent at the younger and older age groups, due to delayed registrations of births and deaths.

Birth estimates

Final estimates of births in a quarter are less accurate than deaths, as deaths are usually registered more quickly than births. Around 5 percent of births are not registered either in the quarter when the baby was born or in the subsequent quarter. As a result, the birth estimates differ slightly from published birth registrations.

Death estimates

The final estimate of deaths in a quarter is taken as those deaths that occurred in the reference quarter, either registered in the reference quarter or in the subsequent quarter. Final estimates of deaths are very accurate as very few deaths (about 1 death in every 1,000) are registered later than one quarter after they occurred. As a result, the death estimates differ slightly from published death registrations.

Population clock

Statistics NZ's online population clock gives a real-time approximation of the estimated resident population of New Zealand. The population clock uses the latest quarterly estimated resident population, and estimates of the expected number of births, deaths, and net migration for the coming quarter. The settings for each component (births, deaths, and net migration) are determined in advance of each quarter, based on recent trends, and will not necessarily reflect actual population change. The quarterly settings are converted into a 'per minute' figure, making allowance for the number of days per quarter.


All figures in this release were rounded independently. Estimates of the total population, natural increase, net migration, and broad age groups are rounded to the nearest 100. National population estimates of five-year age groups are rounded to the nearest 10.

All derived figures in this release use data of greater precision than that published.

More information

See information about the population estimates (DataInfo+) for more detailed information on the methods used to calculate the estimates.

Statistics in this release have been produced in accordance with the Official Statistics System principles and protocols for producers of Tier 1 statistics for quality. They conform to the Statistics NZ Methodological Standard for Reporting of Data Quality.


While care has been used in processing, analysing, and extracting data and information in this publication, Statistics NZ gives no warranty it is error-free and will not be liable for any loss or damage suffered by the use, directly or indirectly, of any information in this publication.

Timing of published data

Our information releases are delivered electronically by third parties. Delivery may be delayed by circumstances outside our control. Statistics NZ does not accept responsibility for any such delay.

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