A new survey shows renters take more than the average number of sick days, which could be the result of cold, damp housing.
The survey of just over 1400 people showed sick days cost the economy nearly $1.4 billion each year.
It also found New Zealanders on average take 3.1 days off sick per year, and those renting took 3.6 days.
The survey found more than a fifth of people had moved out of a home because of cold, damp or mouldy conditions, and 14 percent said the state of their home contributed to their or their family's illness.
Labour housing spokesman Phil Twyford says it shows the state of rental housing is appalling.
"Many of them are cold, damp and mouldy, and it's not only taking a significant impact on the health of the population, but what this survey shows is that it's at a significant financial cost to the country."
Mr Twyford says the Government refuses to legislate standards for ventilation and a modern heating source.
"They had a chance to vote for that with [Labour leader] Andrew Little's Healthy Homes Guarantee Bill in Parliament, but National voted that down.
"We've allowed essentially an unregulated market in rental housing to deliver a product that is a threat to the health of the people living in it."
The survey was conducted by heat pump brand HRV and the Auckland University of Technology.