Many landlords are quick to hike rents but slow to fix homes, a new survey has found.

The Green Party survey found renters are dealing with damp and mouldy houses, rent rises and insecure tenancy.

The party says successive governments have failed New Zealand's 1.4 million renters, and is promising a Renters' Rights Bill if part of the next government.

The survey found in Wellington, one in five renting households pay more than 50 percent of their weekly income on rent.

Tania, who previously rented in Aro Valley, told RNZ the state of one house was so bad she and her partner moved out. She said parts of the house were unstable, damaged and damp.

The list of problems was numerous - a fireplace with cracks so big you could fit your fingers in them, a deck that was falling apart.

But their complaints were dismissed.

Tania says there was a leak in their bedroom which they advised the landlord of.

"Their response basically was like 'Oh, it seems intermittent and it's probably only happening when the wind blows in a different direction'."

The bathroom was also in a state.

"There was a window in the shower basically, that was wood, that would get wet and grow mushrooms."

Tania says she took photos of all the different mushrooms that grew while she lived there.

She says landlords with multiple properties are making a lot of profit, so they need to treat their houses like a business and invest.

In some cases, she says "it's quite apparent that rather than investing in repairing or maintaining these properties, they're just kind of degrading them".

The government's new Healthy Homes Standards for heating, insulation and ventilation came into effect in July 2021 - but landlords have until 2025 for existing tenancies to comply.

James, who has been renting for around a decade, says most of his leases are only for a year, with each renewal met with a rent increase. He says he's currently at a point where he can't afford another increase.

But cost is not the only stress for tenants. He says there is also the fear a landlord will not renew the lease - which leads to tenants tiptoeing around their own homes to ensure there is no "just cause" to be kicked out.

"That can be extremely anxiety-inducing and debilitating, and I feel quite powerless at the end of the lease cycle."

He says very few landlords allow pets these days, which adds more stress on him as a pet owner. If he's not able to stay in his current flat, he would likely have to move back in with his family.

Wellington Property Investors Association president Peter Ambrose says rent hikes can reflect the costs landlords face. He says passing those costs onto tenants is how landlords keep their rentals to a high standard.

Conversely, Ambrose says landlords also need to do whatever maintenance is required.

Ambrose says it's unacceptable for landlords to rent properties which should not be lived in, and maintaining them is ultimately basic human rights.

-Krystal Gibbens/RNZ.