More than a third of Māori and Pacific people were living in damp housing at the time of the 2018 census.
The findings have been revealed by Statistics NZ, following its first ever nationwide data collected on household damp and mould.
It found that when the Census was taken in March 2018, 35.5 percent of Māori and 37.3 percent of Pacific people were living in damp houses, compared with just 22.3 percent for New Zealand overall.
The Census asked the degree to which a house was damp, sometimes damp, or always damp. Dampness is defined as when a dwelling feels or smells damp or has damp patches on the wall, ceiling, floor or window frames.
The data also shows 29.2 percent Māori and 34.7 percent Pacific people were living in homes with mould larger than a sheet of A4-paper either sometimes or always at the time of the 2018 Census.
Senior manager census data delivery Susan Hollows said the data revealed disparities across ethnic groups in Aotearoa.
And dampness can be accompanied by the presence of mould.
"Previous research has shown that cold, damp, and mouldy homes adversely impact whānau health and wellbeing," she said.
"Indoor dampness and the presence of mould in the home have been linked to serious health conditions, such as asthma, respiratory infections, and rheumatic fever."
The highest rates of Māori and Pacific people living in damp houses were seen in the district health board areas of Northland, Counties Manukau, Waikato, Auckland, and Lakes.
The data also shows children and teenagers between up to age 19 were more likely than other age groups to have been living in homes with mould. In comparison, people over 60 years old were the group least likely to be living in mouldy homes.
Hollows said the information can give a clearer view of housing conditions for Māori and Pacific people, and could be used by council's and district health boards for future discussions on health and wellbeing strategies.
"It's helping us identify those vulnerable communities that are really impacted by damp and mould in their homes," she said.
"And I think that is really important with us going into winter."
Director-General of Health Dr Ashley Bloomfield today said damp homes were particularly a concern over winter.
"Part of it is the damp and cold and it's also of course ensuring that people are able to heat their homes, so that particularly for children and older people that they're not in these sorts of conditions that do make them more susceptible to respiratory illnesses.
"It is an ongoing issue... we are making progress and I'm still bothered that there are damp, cold houses in New Zealand."