A study suggests landlords are blocking tenants, many of them Maori and Pasifika, from having healthier dryer homes.
The study by the School of Medicine surveyed 160 tenants and homeowners in Wellington to determine why owners had a higher health status than renters.
Faye Sherwal, a fourth-year medicine student and project leader, said both groups had the same level of knowledge of how poor housing conditions, such as overcrowding and dampness, can lead to illnesses such as rheumatic fever.
However, Ms Sherwal said many people renting felt their landlord was not willing to make improvements because of costs.
The study also found more renters relied upon less efficient heating such as plug-in heaters, whereas most owners used heat pumps or wood burners, she said.