New research is drawing a link between poor quality housing and hospital admissions for under two-year-olds.
The University of Otago study found almost 20 percent of admissions for acute respiratory infections could be prevented if homes were damp and mould-free.
Lead author Tristram Ingham told Newshub GPs and DHBs are powerless to address home environments.
"This research really is a wake-up call that we need solutions to be able to address the health - and particularly the environmental health - of children, so that they get a good start in life."
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In 2015, 9003 children under two were hospitalised in Wellington - about 7.6 percent of all kids that age.
The study drew data from 2011 to 2013. The researchers said damp and mouldy homes cost nearly $8 million a year in hospital costs for under-twos - around 1700 a year.
Dr Ingham says GPs are often powerless when they see children with severe respiratory infections.
"We know that we're also having to send them back to homes where there might be water running down the walls, mould on the curtains and ceilings, and temperatures that are not deemed healthy."
About half of all GP consultations for under-twos involve respiratory illnesses.
"This study really shows that you can't ignore the living situation of children."
The research was published in journal Thorax on Thursday.