Unflued indoor gas heaters should be banned from sale for the sake of children's health, the Nelson Marlborough District Health Board (DHB) says.
In a report on warm homes and clean heating released yesterday, the DHB said a ban would improve standards of living.
The heaters - which burn gas to produce heat - have no chimney to funnel the combustion products outside.
Chief medical officer Nick Baker said young children in the district were admitted to hospital daily with severe respiratory illness, with some cases linked to babies living in cold, damp houses with unflued gas heaters, which robbed them of clean air.
"At this time of year we're getting three to four children admitted each day with respiratory illnesses, typically (babies) under-one, and this particular season we seem to be getting a lot of four month-olds for some reason."
Health board figures showed that asthma was the most common cause of hospital admissions in children across the country, and the disease costs about $1200 a day to treat an affected child.
The economic cost of asthma is more than $800 million a year, according to a 2001 report by the asthma foundation and Medical Research Institute of New Zealand.
Dr Baker said the problem with unflued gas heaters was that all the fumes and condensation from burning gas was released directly into the home.
"This is at a time when families are trying desperately to keep warm, so they don't ventilate their houses properly, and this means you get a lot of toxins building up, damp home accumulate mold, and it's just not the healthy environment kids deserve," he said.
Board member Gerald Hope said the problem heaters were typically LPG fuel heaters, and the board should fully endorse banning them.
The Canterbury DHB has already supported a ban on unflued heaters.
A 2010 review of unflued gas heaters found community groups, such as Plunket, the Tenants Protection Association, Consumer NZ and the Ministry for the Environment, wanted them banned. The review also showed that the Ministry of Health, public health organisations and The Warehouse Group actively discouraged use of the type of heater.
The Nelson Marlborough DHB report recommended replacing inefficient or polluting heating sources, such as unflued gas heaters and older wood burners, with either flued gas heating systems, low emission wood burners or electric heating.
Air quality regulations have led local authorities around New Zealand to introduce strict rules around woodburners, which, in some areas, has led to a total ban on installing even new generation burners.
The DHB report said New Zealand and Australian studies found a "significant reduction" in nitrogen dioxide levels and asthma symptoms through the replacement of unflued gas heaters in homes and schools.