• Population size and growth
• Components of population change
• Fertility
• Distribution of the population
• Ethnic composition of the population
• Age and sex structure of the population
• Households
• Families with children
• New Zealanders experiencing disability
• Gay, lesbian, bisexual and transgender people

Age and sex structure of the population

Just over half the New Zealand population (51 percent) is female. Males outnumber females among children and youth, but females predominate among adults. More males are born than females, but males have higher mortality rates than females at all ages, particularly at ages 20–29 years. The imbalance in the middle years is partly an outcome of sex differences in net migration. At older ages, the difference reflects higher male mortality rates.

Figure P3 Population, by age and sex, 2005

Source: Statistics New Zealand 

The New Zealand population is ageing: the median age of the population was 36 years in 2005, and is expected to rise to 39 years by 2015, then rise more slowly to reach 41 years in 2025.⁸

The proportion of the population under 15 years of age has declined from 25 percent in 1985 to 22 percent in 2005 and is expected to fall to 19 percent by 2015. The population aged 65 years and over has increased from 10 percent of the total population in 1985 to 12 percent in 2005 and will reach 15 percent by 2015 and 19 percent in 2025, assuming medium fertility, medium mortality and an annual net migration gain of 10,000 from 2009.

Population ageing within the working-age group (15–64 years) will be partly offset over the next decade by the entry of the "baby blip" – the relatively large generation of babies born around 1990 – into the young adult age groups. By 2015, the 15–24 years age group is expected to be 5 percent larger than it was in 2005. Over the same period, there will be a slight decline (of 4 percent) in the number of people aged 25–44 years, and an increase of 22 percent in the population aged 45–64 years. By 2015, 45–64 year olds will make up 40 percent of the working-age population, compared with 35 percent in 2005.

Age structure varies by ethnic group. In 2001, the European ethnic group population was the oldest, with a median age of 37 years, followed by Asians (28 years), Other ethnic groups (26 years), Māori (22 years) and Pacific peoples (21 years). By 2021, half of all Māori will be older than 26 years and half of all Pacific peoples older than 24 years. Over the same period, the median age of European and Asian New Zealanders is expected to have risen to 44 years and 36 years, respectively.⁹