An independent hygienist has assured parents of students attending Australia's oldest school that any potential exposure to asbestos has been low.

Key points: Experts believe student exposure to asbestos is low after it was discovered at Newcastle East Public School

Experts believe student exposure to asbestos is low after it was discovered at Newcastle East Public School The NSW Government has apologised to parents for poor communication on the issue

The NSW Government has apologised to parents for poor communication on the issue More answers will be provided within 48 hours of a community meeting held last night

Angry parents and neighbours fired heated questions at the New South Wales Government and experts last night at an information session at Newcastle East Public School, amid an asbestos crisis.

Last week, they were told asbestos had been discovered in the roof of one of the heritage buildings, but hygienist Josh Trahair said the asbestos identified was not loose-fill insulation and said, following testing, he was confident the school was safe.

"Based on the current data, any exposure risk is considered to be very low," Mr Trahair said.

"However, without historic monitoring data we simply can't quantify the actual exposure to staff and students — it can really only be [an] estimate."

The initial discovery of the material led to further detections, and the decontamination of multiple school blocks, along with the disposal of several items including library books and sports equipment.

An unprecedented level of testing had since taken place, which saw more than 2,500 samples collected.

No safe levels

Occupational hygiene expert Nathan Redfern explained to parents that everyone would be exposed to asbestos at some time in their life, and that low-level asbestos was present in water, air and soil.

"Most people do not become ill from their exposures," he said.

"Those who do become ill from asbestos are usually those who are exposed to it on a regular basis, most often occupationally," he said.

The samples that tested positive for asbestos were not free fibres. They were in a bundle, meaning they were not breathable.

"When they're in a bundle, it means they're grouped together and they can't actually get that far down to your lungs, and you end up coughing them up or bringing them up through other methods," Mr Redfern said.

He said he was not trying to downplay the risk of asbestos, but said there was no actual level at which a person could constantly be that would not put them at risk.

When it comes to surveying asbestos exposure in children, it's more complicated and is usually done by a GP.

"They would take information down, the dates of possible exposure," Mr Redfern said.

"Some of the tests required, like chest X-rays and the like, are not recommended for children."

Minister apologises

Minister Sarah Mitchell and Education Department secretary Mark Scott apologised for poor communication on the issue. ( ABC Newcastle: Grace Bird )

The NSW Government promised to answer more questions about asbestos exposure at the school by tomorrow night.

Education Minister Sarah Mitchell apologised to enraged parents and neighbours at last night's meeting.

Ms Mitchell said items destroyed as a result of the clean-up would be replaced, and more information would be provided to parents.

"I understand that there is a lot of distress and I think part of that has been a lack of communication, which I apologise for," The Minister said.

"What we've undertaken to do is any question that has been asked, there will be written documentation provided back to this school community by Wednesday evening.

"Not just to the work that's happened over the school holidays, but some more historic questions."

NSW Department of Education secretary Mark Scott admitted communication on the issue had been poor.

He said detailed documents about the discovery and removal process would be released to the school community.

"We've learnt our lesson, I think, about the need to extensively communicate and explain to school communities when any asbestos is found on a school site, have clear policies and protocols in place," Mr Scott said.

"Yes, fibres were found, our advice is that it was well below threshold levels that would cause concern and well below threshold levels that may exist in any building you would find anywhere.

"We received absolutely no advice that the school was not safe to open."

Parents fear for children

A respiratory physiologist and parent of three students at the school, John Brannan, said there needed to be a bigger effort to monitor heritage buildings.

Several questions remained about potential exposure in the past and he said it was a big problem.

"Acute exposure is one thing but repeated exposure is another," Dr Brannan said

Parent John Brannan is concerned about past exposure to asbestos at the school. ( ABC Newcastle: Grace Bird )

"While we've discovered that there's asbestos present in this building, my concern is what's been happening in the past and whether the children have had repeated, low-level exposures that may be influencing their health in the future.

"Small lungs that get exposed very early means the disease process may take hold a lot sooner and we may see a result in a shorter space of time.