The proportion of couples living without children is increasing and expected to make up more than half the extra 433,000 families expected to be in New Zealand by 2038.
This family type, which also includes couples whose children have left home, will drive the increase in most areas, Stats NZ said today.
New Zealand will have 1.7 million families in 2038 under the mid-range projection.
"While growth in the number of families reflects our growing population, the changing composition of families is driven by our ageing population," said population statistics general manager Peter Dolan. "Many more people will be in the age where their children have left the family home. These are the so-called 'empty nesters'."