Wellington City Council is launching a voluntary warrant of fitness scheme for rental housing in the city.
The council has teamed up with public health experts from the University of Otago in a bid to raise the standard of rental properties.
Wellington mayor Justin Lester said the scheme was the first of its kind in the country.
"We want to lift rental standards in our city and make better accommodation available for people. Every Wellingtonian deserves a warm, dry home," Mr Lester said.
Landlords would be able to book an inspection online, and if the house failed they would have six months to make the necessary changes to meet the scheme's criteria.
The inspection would cost $250 and the warrant would be valid for three years.
Speaking on Morning Report, Mr Lester said the average Wellington flat cost about $500 a week to rent. The warrant would ask 29 questions, and charging $250 against average annual rental income of $25,000 was not a lot of money, he said.
''This isn't asking the Earth, it's that there's no rainwater ponding under the house, that the toilets work, that there are secure locks on the doors, that there are latches on the windows ... insulation in the ceilings and insulation in the walls as well.
''We're not asking the Earth. These are basic requirements.
''This is a good start. This is a tool for landlords as well. If I've got a home and it's vacant and I'm trying to market it to prospective tenants, I can then put the certification up against my property on Trade Me and say 'this meets the rental warrant of fitness'.
''And for tenants that's a great sign.''
A trial involving councils a few years ago indicated the vast majority of rentals, which Mr Lester estimated at 90 percent, failed a warrant test.
''A good chunk of them did fail but they failed on basic things. So they might have had to just put a window latch on, for example, they might have had to fix a toilet.
''Most houses with some basic improvements will meet the rental warrant of fitness.''
Regarding investors and landlords, Mr Lester said most people he had talked to thought the opt-in warrant was reasonable.
''I think most people understand, again this is voluntary and this is a good tool to improve the quality of accommodation
''Look, no-one wants to own a home that's cold, or that's damp or that's mouldy.''
Mr Lester said the council would launch an app to allow tenants and landlords to check their houses against minimum health standards, and allow landlords to request a full inspection by a professional to be certified as meeting the standard.
"This will give landlords the chance to promote their house as being warm and dry, and give prospective renters an assurance the home they are looking to live in meets the standard."
Health and housing expert Philippa Howden-Chapman, a public health professor at the University of Otago, Wellington, said it was a win for renters.
"The rental warrant of fitness is the first scheme in the country that's taking action and helping raise the standards of our homes. It focuses on areas of the home that we know have the greatest chance of improving the occupants' health."
She said the assessment would cover insulation, heating, ventilation, hazards and more.
The rental warrant of fitness will be launched on 28 August.