Population aged 18 and older

IBISWorld forecasts the New Zealand population aged 18 and older will increase by 1.2% during 2025-26, to reach 4,187,800 people. Exposure to a global uncertainties and recessionary risks have heightened concerns in the current year. For example, housing supply and inflationary concerns have remained at the forefront, partially limiting net migration. Nevertheless the natural growth of the population aged 18 and older has been supported by advancements in healthcare and medical technology, which have allowed for an expansion of New Zealand's life expectancy.

In addition, extended periods of border restrictions significantly constrained non-New Zealand citizen migration into the country. However, the removal of international border restrictions in 2022-23 provided a catalyst to contribute to an increase in net migration, driving growth in the population aged 18 and older.

The size of this age demographic has increased at a faster pace than the overall population over the past five years. However, this growth has been somewhat limited by the decline in the number of births during the early 2000s. A conmination of family formation postponement and cultural shifts towards dual-income families and contraception use made this lower birth rate set in. The population aged 18 and older is expected to account for 77.5% of the New Zealand population in the current year. This proportion has risen from 76.9% in 2020-21. Overall, IBISWorld forecasts the New Zealand population aged 18 and older to increase at a compound annual rate of 1.3% over the five years through 2025-26.