Auckland landlords say rental property owners are being unfairly singled out by Labour's Healthy Homes Guarantee Bill.
Labour leader Andrew Little's bill passed its first reading in Parliament this week and would require landlords to properly heat, insulate and ventilate their properties.
Auckland Property Investors Association vice president Peter Lewis told TVNZ's Q+A programme today there's no standard for owner-occupiers and that's not fair.
"To us, it's like saying only green cars on the road have to have a warrant of fitness, and no other car does," Mr Lewis said.
"I understand bringing in a housing standard for every house in the country - that makes sense. Why just pick on rental homes?"
Mr Lewis says landlords are effectively small "ma and pa" business owners and they can't afford to meet the cost of Labour's proposed standards.
Mr Little says the bulk of people on low incomes and those in poverty are living in rental accommodation, much of it private.
"The starting point has got to be 'here are the standards'. And it's not good enough just the have insulation because all that does in the middle of winter [is it] traps in the cold air. You've got to have a source of heating, you've got to have ventilation," he told Q+A.
Mr Little says ensuring quality rentals is a consumer law issue about ensuring people who sell accommodation into the market are operating at a minimum standard.
The Children's Commissioner, Dr Russell Wills, estimates there are 42,000 hospital admissions and 15 deaths a year of children with conditions associated with poor housing and poverty.