New healthy homes standards for rental properties have been described as "brilliant" by one Northland social advocate.
However, the changes could see rents rise as landlords look to pass on costs.
Housing and Urban Development Minister Phil Twyford announced the new standards, which set minimum requirements for heating, insulation, ventilation, moisture and drainage, and draught stopping in residential properties on Sunday.
Under the new standards, all rental homes will be required to have a heater that can heat the main living area to 18C, kitchens and bathrooms will have to have extraction fans or range hoods, and ceiling and underfloor insulation must be at least 120mm thick or meet the 2008 building code.
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Twyford said making sure all New Zealanders had warm, dry homes was one of the most important public health changes the Government could make.
"Nearly 600,000 households rent in New Zealand, and our rental stock is of poorer quality than owner-occupied homes. It's estimated about 200,000 families live in rental homes that do not have ceiling or underfloor insulation."
Figures released last week by the Ministry of Housing and Urban Development show 445 people were on the public housing register in Northland in the December quarter last year - an increase of 117 per cent compared with 191 people at the end of 2017.
The latest Massey University Home Affordability Report showed Northland is the second worst when it comes to affordable homes.
"The Ministry of Health says 6000 children are admitted each year for 'housing-sensitive hospitalisations'," Twyford said.
Twyford said the standards are "pragmatic, enduring and don't impose an unreasonable burden on landlords and industry".
From July 1 2021, private landlords must ensure that their rental properties comply with the standards within 90 days of any new tenancy. By July 2023 all Housing New Zealand homes must comply.
Twyford said that Housing New Zealand has 68,000 properties, and it will need to spend more than $200 million, which will come off its books.
"We've set three years from now, basically, they have to have all their houses being compliant."
One Double Five Community House's Carol Peters said the new standards were "a brilliant thing" but added that many good landlords were doing it already.
"It's not only good for people in the house but it's good for the house."
One example is the extractor fan stops mould growing.
Peters said the new requirements were really important for those who were homeless.
"They struggle to get into housing so they accept anything, so they accept sub-standard housing."
She thought the move would reduce hospital admissions for illnesses like asthma, as well as reduce the colds, coughs and flus that people get.
"Tenants will feel cared for in having a better house."
She said the new requirement's shouldn't mean an increase in rent for tenants.
"Landlords should care for their tenants, and a lot of landlords are already."
New Zealand Property Investors' Federation executive officer Andrew King said they were supportive of improving standards but wanted them to be cost-effective because ultimately the costs will be passed on to tenants.
Paul Beazley, from Eves Whangārei, who manage hundreds of properties on behalf of landlords said it was difficult to work out what the costs to landlords would be because there was a lack of detail in the standards required.
"Most landlords and property owners won't be affected because they've got their property up to standard."
Beazley said if costs start to go higher, rents will go higher, but he didn't think they would go up significantly.
"There probably will be some pressure on the rents. Landlords will pass on the cost."