A year after the 2023 census, changes were already taking place in New Zealand’s population that meant the data was in danger of being superseded.
Fertility was continuing to decline, the number of immigrants arriving was beginning to climb, there was an exodus of New Zealand citizens, Māori made up more of the population and Asian communities were continuing to grow.
Eighteen months on, we need to revise the picture again. As is often the case with New Zealand, a period of supercharged population growth fuelled by immigration has been followed by a slump.
In the year to February 2024, StatsNZ was reporting immigrant arrivals at an all-time high of 253,200, with a net gain for the year of 130,900.
This surge produced population growth for the 2023 year of 2.3%, compared to the average for all OECD countries of 0.7% . Migration made up more than 85% of this population growth, with natural increase (births minus deaths) the lesser factor.
In 2023, only two OECD countries, Canada and Iceland, exceeded New Zealand’s population growth. Other countries actually saw population decline, notably Germany and Japan.
The latest data shows a major reversal in both immigration numbers and therefore population growth. In the year to September 2025, arrivals were down at 138,900, and the net gain was 12,400.
Population growth was tracking at 0.7%, so the same as the overall average for the OECD.
More are leaving – or not staying
Not only are there fewer arrivals, but the number leaving New Zealand has spiked.
Overall, departures are now tracking at 126,400, up 10% on the year before.
What is concerning are the number of New Zealand citizens leaving. For the 12 months to September 2025, 72,700 left, with an overall net loss of 46,400.
The last time we saw such figures was at the back end of the Global Financial Crises in 2011-12. Then, 72,401 New Zealand citizens left, with an overall net loss of 44,385.
But non-New Zealand citizens are also leaving in greater numbers. The 2025 figure is up by 17% on the year before.
It’s most likely that economic circumstances, combined with the opportunities available elsewhere (especially on the other side of the Tasman), are a major contributor to these outflows.
Stagnation, even depopulation
This drop in immigrant numbers, combined with migrant departures, has reinforced an important dynamic – migration is crucial to both the population growth of the country but also that of cities and regions.
In the year to June 2025, natural increase now makes a more significant contribution to population growth (21,000 per year), while net migration is now down at little more than 12,000 per year.
Population growth is now confined largely to the regions with major cities –Auckland, Waikato and Canterbury. Wellington and Taranaki are experiencing population stagnation (no growth), while Nelson,