Births and Deaths: Year ended June 2011

Technical notes


Births data from 1991 are based on births registered in New Zealand to mothers resident in New Zealand by date of registration. Before 1991, births data are based on births registered in New Zealand to mothers resident in New Zealand and mothers visiting from overseas by date of registration. Births data exclude late registrations under section 16 of the Births, Deaths, Marriages, and Relationships Registration Act 1995. Section 16 births are those that were not registered in the ordinary way at the time the birth occurred. For more information about the history and characteristics of late registrations see Late Birth Registrations


The Births, Deaths, Marriages, and Relationships Registration Act 1995, which took effect from 1 September 1995, redefined a stillbirth as a child who is born dead and weighs 400g or more or is born dead after the 20th week of gestation. Before the new Act, a stillbirth was defined as a child born dead after 28 weeks of gestation. This change in definition means that stillbirths from September 1995 onwards are not directly comparable with earlier years.


Deaths data from 1991 onwards are based on deaths registered in New Zealand of New Zealand residents by date of registration. Before 1991, deaths data are based on deaths registered in New Zealand of New Zealand residents and people visiting from overseas by date of registration.

Replacement level fertility

Replacement level fertility is the average number of children a woman needs to have to produce one daughter who survives to childbearing age. Replacement level fertility is also described as the total fertility rate required for the population to replace itself in the long term, without migration.

The internationally accepted replacement level is 2.1 births per woman. Replacement level fertility allows for child mortality (children who die before reaching reproductive age) and the birth of more boys than girls. On average, throughout the world, 105 boys are born for every 100 girls. The actual replacement level will vary slightly from country to country, depending on child mortality rates. In countries with high child mortality, the total fertility rate will need to be higher than 2.1 births per woman to achieve replacement level.

Total fertility rate

The total fertility rate is the average number of live births that a woman would have during her life if she experienced the age-specific fertility rates of a given period (usually a year). It excludes the effect of mortality.

Children of this relationship

The birth registration forms ask whether there are any other children of this relationship. However, it is possible that children from previous relationships are included. This question does not produce an accurate measure of all live births to a woman (needed for accurate measures of birth parity). For privacy reasons it is deemed unacceptable to ask women about children outside their current relationship.

Standardised death rates

The overall death rate that would have prevailed in a standard population if it had experienced the age-specific (usually age-and-sex-specific) death rates of the population or area being studied. In this information release, the age and sex distribution of the mean estimated population for the year ended 31 December 1961 is used to derive standardised death rates.

Life tables

A life table provides a detailed description of the mortality experience prevailing in a population during a given period. It comprises an array of measures, including probabilities of death, probabilities of survival and life expectancies at various ages. Complete life tables present mortality measures for each single year of age, while abridged life tables present mortality measures for age groups. 

National complete period life tables are produced every five years for Māori, non-Māori, and total New Zealand male and female populations. Subnational abridged period life tables are also produced every five years for the male and female populations. They are available for all 16 regions and most territorial authority areas (where death and population numbers are sufficient to construct reliable life tables). National complete period life tables and subnational abridged period life tables for 2005–2007 are included in the New Zealand Life Tables: 2005–2007 report, released in May 2009. The report also includes details on life tables methodology.

National abridged period life tables are produced annually for the total New Zealand male and female populations and provide an indication of the trends in life expectancy in the years between the construction of complete period life tables. 

Demographic rates

Demographic rates from 1991 onwards are calculated using the mean estimated resident population. Rates before 1991 are calculated using the mean estimated de facto population.

Demographic rates based on the mean estimated resident population are provisional for the reference period of this information release because the population estimates used to calculate the rates are provisional. Publication of final rates in Infoshare will coincide with the publication of the next information release. The difference between provisional and final rates is generally small (less than plus or minus 1 per 100,000). 


Birth and death figures contained in the tables attached to this information release are unrounded. All other figures have been rounded. This may result in a total differing slightly from the sum of its components. Derived figures (for example percentage annual increase) have been calculated using unrounded data.

Free online database

A number of  births, deaths, and birth and death rates tables are available through Statistics NZ's Infoshare database (, a free online tool that provides access to a range of time-series data. The births, birth rates, deaths, and death rates subjects can be found under Population on the Browse page of the database.  

More information  

More information about births and deaths is available on our website.

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