The majority of people living in overcrowded homes are Pacific, mainly Tuvaluans and Tongans.
From the 2013 Census, 398,295 people were living in overcrowded houses, mostly in South Auckland.
Crowding was highest among Tongans with 48.7 per cent living in crowded homes.
Photo/ RNZ Checkpoint.
Senior analyst Dr Rosemary Goodyear says around four in 10 Pacific people live in this housing condition and it has a negative impact on health and education.
"Living in crowded households relate to ill-health particularly high rates of infectious diseases," she says.
"People in crowded households were significantly more likely to say they didn't have enough money for everyday needs like postponing visits to the doctor because of the costs, not having enough money for fresh fruits and vegetables."
"Being in a crowded house and not having the space and peace to study can also affect the education of children."
Dr Goodyear says they're unsure what Census 2018 will reveal.
"We do know with the increase in pressure of housing in the last few years it's probably unlikely to have changed significantly."
She says the statistics have slightly decreased over the years for Pacific people, but overall the overcrowded-homes statistics have remained unchanged over the past 10 years.