Māori and Pasifika children made up two thirds of children under two hospitalised with a respiratory infection, according to a new study.

A research team that checked the houses of sick children for mould and dampness has provided more proof bad housing in New Zealand is linked to childhood disease.

A Otago University study looked at Wellington children who were taken to a doctor with a respiratory infection.

A building inspector checked the homes of 642 children under two years old, including controls, and found children were up to five times more likely to be hospitalised if they lived in homes where dampness, mould and water leaks were detected.

Māori and Pasifika children made up two thirds of those hospitalised.

Dr Tristram Ingram says in 2015, 7.6 per cent of New Zealand children in this age group were hospitalised because of a respiratory infection.

His study found almost 20 per cent of those hospital admissions - or 1700 children - could be kept from getting that sick, if their homes were safe from mould and dampness.

That would save the health system $8 million in direct hospital costs alone, as well as relieving the stress it created for families, he says.

"Every kid gets a cough or a sneeze, but about 7 per cent get seriously unwell, and end up in hospital as a result of those kind of infections. Those hospitalisations are about double the rate of other OECD countries, and still rising.

"Evidence shows children who get repeated respiratory disease can get scarring of the lungs that can lead to adult lung diseases, costing more down the line.

"So what I think is really necessary is for each of our GPs and clinicians to be thinking about, and asking about home conditions in relation to respiratory infections. It is the bane of our lives to send children with these kind of conditions home to cold and damp houses."

Photo: Supplied / University of Otago

Tristram says it adds to mounting proof that poor housing is contributing to diseases burdening our health system and families. And better heating, ventilation and insulation could all help improve damp and mouldy homes.

"There are things that you can do, but ... the problem really is rental affordability at the moment is pretty high, it's pretty hard to afford rental accommodation. And the policy response from government, while it's fantastic in terms of getting houses insulated, and ensuring the rental warrant of fitness is put in place, my significant concern is that these costs are going to be passed on through landlords to the actual renters themselves.

"And these are the people who we know can least afford to pay for the retro-fitting of our pretty decrepit housing stocks."

One third of the children hospitalised were Māori, and one third Pasifika, a finding that was "really startling.

"I think what you're seeing is a disproportionate burden of respiratory ill health - and socio-economic factors clearly play a role in this.

"We know that all New Zealand families want their kids to get a good start in life, but if these tamariki are being disproportionately affected by respiratory health complications early in life, we are not setting up our children for a good start in life."