New figures show more couples are choosing to forgo having children.
Couples without kids account for more than half the projected growth of all families, likely increasing from 513,000 in 2013 to 757,000 in 2038, according to numbers released by Statistics NZ on Friday.
In 2013, 41 out of 100 families were couple-without-children families and this is projected to increase to 45 out of 100 families by 2038.
"Couples whose children have left the parental home - the empty-nesters - are expected to be the most significant factor in the growth of couple-without-children families," population statistics senior manager Peter Dolan says.
Couple-without-children families include couples with no children and those who have children living elsewhere.
Meanwhile, two-parent families are expected to drop to 38 families in 100 in 2038, from 40 in 2013.
One-person households are expected to be the fastest-growing configuration over the next two decades, increasing from 393,000 in 2013 to 599,000 in 2038.
More than a quarter of all households are expected to consist of a single person in 2038. The average household size will decrease from 2.6 people to 2.5. In 1951, it was 3.7, and in 1980, three.
The Statistics NZ figures also project New Zealand would reach 2 million households by 2027, a rise of 596,000 households from 2013.
Mr Dolan said this growth is mainly due to the ageing population, with large growth expected in the number of over 65s between now and 2038.
Statistics NZ says the future figures are not predictions, and are based on existing trends.
NZN / Newshub.