Thousands of children are being re-admitted to hospital every year because of poor living conditions, a child health specialist says.
In a 50-page paper released today, the Royal Australasian College of Physicians has called on politicians to do more to address the causes of health inequity in New Zealand.
Too many people were living in cold, mouldy and over-crowded homes and it was ruining the health of children in particular, the college said.
Palmerston North paediatrician Jeff Brown said he was seeing an increase in repeat hospital admissions for children with respiratory illnesses, including pneumonia, caused by poor housing.
"We are struggling. It's over-burdening our hospitals, our GP surgeries," he said.
"That is something that could be changed, could be affected, and if we had better home circumstances, better communities to live in, we would not be seeing what we are."
Dr Brown said making children better only to have them return later was demoralising to doctors.
"One trainee is taking time out of medicine now. She can't really face the fact that she can do her very best as a doctor and then sends the kids back and she can't alter the circumstances where they came from."
Urgent action on health equity was the top issue for him this election.
"At the moment there's this argument, 'Oh no, we'll self-regulate. Oh no it's [an] infringement on personal rights or the market will sort it out.' Well it hasn't."
The college's New Zealand president, Auckland cardiologist Jonathan Christiansen, said doctors were treating patients who are struggling with preventable illnesses every day.
"Cold, old, damp and mouldy houses directly links to poor health through respiratory illnesses, and those illnesses affect vulnerable groups in our society like children and elderly people and can exacerbate their other health conditions."
That was especially bad in winter, Dr Christiansen said.
More than 40,000 people were living in precarious, insecure housing, including garages, sheds and caravan park, he said.
That was fuelling a widening health gap among different groups in society.
"Those who are most vulnerable and under-privileged in society have the worst health, they die earlier, their mortality rates are higher, their hospitalisation rates are higher, their mental health rates are higher," Dr Christiansen said.
College members wanted politicians to introduce a warrant of fitness and health for homes; targeted assistance for low-income families to help them with power bills; more public housing for low-income people; and wider adoption of the living wage.
Some initiatives along those lines had been attempted but had not been sustained, Dr Christiansen said.
"They've not been coordinated and they've not been spread widely enough to make an impression on really the relentlessly poor and atrocious living circumstances that many of our New Zealanders are in."
Public Health Association chief executive Warren Lindberg backed the doctors' demands, saying the costs of not doing more were too high.