New Zealand has had its largest-ever population increase: 145,100 new Kiwis arrived in the year to December 2023.

It is the largest increase since the data series started in 1991 and puts New Zealand’s population at 5,305,600.

The previous largest increase was in 2016 when the population grew by 103,900 to 476,7600.

Just 19,100 of the most recent increase was because of a “natural population increase”; migration accounted for 126,000 new people.

30–44 year old population surges

New Zealand population, population increase, and percentage change in population for five yearly age bands in the year to December 2023.

The biggest increase was in 35 to 39-year-old men, with 8.9 per cent more of them than last year.

Women in the same age group increased by 6.6 per cent.

The second largest increase (6.9 per cent) was among the 75 to 79-year-old group. The reason for this appears to go back to World War 2.

The 35 to 39 age group had growth across all age groups, including among those who turned 40 in 2023 and graduated to the 40 to 44 age group. But the 75 to 79 age group saw no change in the number of 75-year-olds between 2022 and 2023 and a drop in 80-year-olds.

Births dropped during, and boomed after, World War 2

Annual live births in New Zealand: 1935–1950

In 1942 and 1943, as World War 2 raged and many New Zealanders were deployed overseas, the number of babies born fell.

This was followed by a “boom” in births every year from 1944 to 1947.

This can be seen today in a decrease in the number of 80 and 81-year-olds in 2023 compared to 2022 - corresponding to babies born in 1943 and 1942 - and large increases in the ages corresponding to babies born between 1944 and 1947.

More new males than females

Percentage increase in New Zealand population by male/female and five-year age band.

The number of men is increasing faster than women in almost all age groups - Stats NZ only provides data for male and female population increases.

The only age range where the number of women grew more than men is in the 75-79 year-old group which also is seeing one of the highest increases overall, coming in behind the 35 - 39 group.

The only age range where women number higher than men is in the 75 to 79 year-old group which also has one of the highest increases overall, coming in behind the 35 to 39 group.

Meanwhile, the annual net migration loss of 47,000 New Zealand citizens in 2023 is a new annual record.

New Zealand has typically had an annual net migration loss of citizens, which averaged 26,600 a year in 2002–2013, and 4000 a year in 2014–2019.

Based on the latest estimates, 53 per cent of New Zealand citizen migrant departures were to Australia.