The NSW government says a decision to replace unflued gas heaters at 100 schools in the coldest parts of the state doesn't mean all 51,000 of them are unsafe.
Installation of the controversial heaters was stopped last month while the government awaits a report on their effect on children's health.
The government has now announced it will now spend $15 million to remove the heaters from 100 schools in areas such as the Blue Mountains, Bathurst and the Snowy Mountains.
But NSW Education Minister Verity Firth has denied the move is an admission the state's low-emission unflued heaters are unsafe.
Nor was it a sign that all 51,000 of them would be replaced, she said.
"For schools in the coldest areas of the state, it can be difficult to provide adequate ventilation while keeping the room warm, so it makes sense to replace the heaters in those schools first," Ms Firth told reporters in Sydney on Wednesday.
"Current health advice tells us that there are no health risks with our low-emission unflued gas heaters as long as they are appropriately maintained, with appropriate ventilation.
"The specific issues of schools in our coldest climates are that they sometimes find it hard to meet those ventilation requirements."
Ms Firth said the decision was based on the lobbying of local MPs, communities and groups such as the Asthma Foundation NSW.
It was not prompted from any health advice, nor from recommendations of a draft Woolcock Institute report, she said.
The report's findings are at least a month away.
Blue Mountains Labor MP Phil Koperberg welcomed the decision, after pushing for the removal of the heaters in his electorate west of Sydney.
Heaters will start being removed in the next few months, with the program to be completed before next winter.
"In high-climate and cold-temperature schools, when it is three degrees below zero, and there is a 30km/h wind blowing, teachers can hardly expect to open the doors and windows," Mr Koperberg said.
"These representations have been made cogently, and decisively and sensibly to the minister and the minister has responded by saying we are going to make a start on this, even in the absence of any indisputable scientific evidence to the contrary.
"This is a good start and should bring relief to the concerns of many parents of children in cold climates."
Community group C.O.U.G.H (Campaign Opposing Unflued Gas Heating) agreed.
"Today's announcement will provide relief for thousands of families directly affected by health impacts on their children at public schools," said executive member and Hazelbrook Public School P&C president Ms Jo Keown.
"The decision is a good beginning, and our expectation is for a quick rollout as winter has definitely begun in cold-climate areas of the state."
But the Greens have accused the government of cutting corners at student hospitals and called for the removal of all the state's unflued heaters in schools.
"This winter no school will experience any relief from the fumes and the asthma attacks and other diseases these heaters cause," Greens MP John Kaye said.
"Only a tiny fraction of NSW schools will be see any benefit from the paltry $15 million allocated for heater replacement, and even these schools will have to wait until next winter."