It's 8.40am and a flustered teacher hurries into principal David Smillie's office.

Another parent at her own child's school has tested positive to COVID-19.

"I don't know if I should be at work," she says, panicked and short of breath.

Three parents are already waiting in the tiny corridor of the administration desk here at The Grange, a primary and secondary college located in Hoppers Crossing in Melbourne's outer west. They're worried about whether their children should be at school.

One of the women's children has a headache, another's child has been vomiting.

David's phone moves to his ear almost before it rings.

This is how he's spent most of the past week, answering calls from more than 80 anxious parents who are demanding answers.

"Since the Prime Minister's statement that schools definitely won't close, I have been inundated with really worried parents," he says.

"They're very confused, they're very scared."

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The Grange has introduced strict handwashing sessions every two hours to try to prevent any spread of coronavirus. ( ABC News: Margaret Burin )

"I do worry but I try not to think about it," secondary student TJ says. "I worry about my parents because they go to work in packing and are in the public." ( ABC News: Margaret Burin )

Outside, in the senior campus yard, there's an unusual energy, not the buzz you'd expect from almost 1,000 rowdy school students.

It's Thursday morning and, shortly after they shuffle into their classrooms, Mr Smillie refreshes his computer to see the morning attendance tally as it comes in.

More than 720 of the school's 1,830 students across both campuses are absent. That's nearly 40 per cent of students away. By Friday, it's fallen again, closer to 50 per cent absent now.

In this classroom, only 11 out of 22 kids showed up. A couple of doors down, there were only eight. ( ABC News: Margaret Burin )

Hand sanitisers and coronavirus information packs have been placed around the school to try to inform and reassure families. ( ABC News: Margaret Burin )

'We're hoping Norman Swan is wrong'

Mr Smillie and his leadership team have been issuing daily social media bulletins aiming to inform and reassure the broader school community. But more and more families are choosing self-isolation, in a bid to stay safe and to slow the spread of coronavirus.

"No matter how much we talk about theories of containment of the virus, people still think because we've got lots of kids on site, they still think the school's a possible area of infection and they worry about their own children.

"They know that the public galleries are closed, they know that politicians are sitting 1.5 metres away from each other, Qantas is closing down, people are working from home, but what do they see here?

"So, we're hoping that the chief medical officer, Brendan Murphy, is correct, and that he's smarter than the rest of the world and we're hoping that Dr Norman Swan on ABC is wrong."

The decision to keep schools open follows the advice of medical experts at the Australian Health Protection Principal Committee, which says young people are at low risk from coronavirus and closing schools could have a 30 per cent impact on the availability of health workers, who would need to stay home to care for their children.

Earlier this week, Dr Norman Swan, host of the ABC's Coronacast, said it would be challenging but he felt closing schools immediately was the right thing to do. He now says it is a tough but inevitable decision that schools will close.

"This week, the numbers in Australia are starting to rise steeply, albeit from a low level," he said.

"We have a few days to play with but very soon, if the curve isn't bending then schools and universities are going to have to shut since the international evidence is that around 30 per cent of infections come from young people.

"And by the way there — sadly — are plenty of young people being ventilated in intensive-care units in Italy and elsewhere."

But for the moment at least, Prime Minister Scott Morrison says it is in the national interest to keep schools open. For Mr Smillie, making that happen is getting more difficult by the day.

Principal David Smillie says if schools are to remain open, the government needs to organise increased cleaning of all surfaces to keep staff and students safe. ( ABC News: Margaret Burin )

News and fear are spreading.

Twenty-two of The Grange's teachers call in sick. Mr Smillie doesn't blame them.

Some are pregnant, undergoing chemotherapy, dealing with conditions that compromise their respiratory or immune systems or have family members who are ageing or sick.

Others are over 60 and worried about what will happen if they contract the virus.

Physical education teacher Rocco Giovanniello says he's kept his own children at home but is forced to go to work.

The school is struggling to get casual replacement teachers to fill gaps. More teachers will be off next week, Mr Smillie has just been informed, as several staff with young children have been told their childcare facilities will close.

"I'd find it challenging to keep the school open with the increasing level of staff absence," Mr Smillie says.

The local council has already closed before- and after-school care programs.

'Schools are not set up for social distancing'

Teacher Agata Kula-Lugg says she's worried about her own family's health and the wellbeing of the school's most vulnerable young people. ( ABC News: Margaret Burin )

Secondary teacher Agata Kula-Lugg, herself a mum of two young children, says she feels the government is relying on the goodwill of teachers to put their students first, without reassuring them there's a plan.

"Aside from concerns about my own safety and my family's safety, I've been following the news very closely for the last three days and there doesn't seem to be any mention of teachers when they're talking about schools.

"Because if they did mention teachers, they'd have to admit that this is completely unsafe.

"Schools are not set up for social distancing."

Classes have had to be restructured, including large library sessions, to cope with the high number of absent teachers. ( ABC News: Margaret Burin )

Other schools are reporting a lack of hand sanitiser and soap. If schools are to remain open, Mr Smillie says the government must organise frequent cleaning of all surfaces, including forensic cleaning of the whole school.

By Friday, at The Grange at least, new cleaning regimes were in place.

The Australian Education Union has demanded an immediate briefing from the chief medical officer about its members' concerns and what actions will be taken if sufficient safety measures can't be implemented.

In a press conference on Wednesday, Mr Morrison pointed to research that Singapore had successfully controlled the virus while keeping schools open. He declared he was fine sending his kids to school.

But Mr Smillie says many in his school community aren't buying it.

"They just don't believe it," he says.

"The problem for me is these are the countries that have closed schools: China, Italy, France, Spain, North and South Korea, Norway, Switzerland, America, the UK.

"I think it's pretty difficult that last week right up until Friday that the Grand Prix was going ahead.

"Then the government makes the decision while a couple of people are queuing waiting to go in, coupled with the toilet paper fiasco, coupled with the bushfires, there's not a lot of confidence with my parents around how decisions are being made."

'Not a risk I'm willing to take'

Linda Flores says she's self-isolating with her teenage girls because she's worried the coronavirus poses too big a risk to her sick father. ( ABC News: Margaret Burin )

Linda Flores is one of the hundreds of parents who's decided to pull her girls out.

Her father has just been diagnosed with early-onset blood cancer and has a kidney infection.

"I'm my dad's full-time carer. If they get something they give it to me or my husband, I give it to him and he ends up in hospital or worse.

"It's not a risk I'm willing to take.

"Also, if I get it and I can't look after my dad, he'd have to employ a full-time nurse and he can't afford that."

Her children will be self-isolating at home until at least after the school holidays, but most likely indefinitely.

"It's not something I would normally do. I am concerned about the impact on exams."

Other parents at The Grange remain confident about continuing to send their children to school, and are vowing to remain calm among the chaos.

Mother-of-three Janet Morrow says she has no fears sending her three sons Ben, Joel and Charlie to school. ( ABC News: Margaret Burin )

Janet Morrow says her three sons need the structure and routine of school.

"I have no fears about the kids staying at school," she says.

"We're not in the high-risk category, we don't have relatives that we see often that would be at risk if we were to get the virus and at the end of the day I'm a human being, I could go out the door, walk across the road and get hit by a car."

Mum and nurse Julie Vernon says she's comfortable sending Madeline to school right now. ( ABC News: Margaret Burin )

Mother-of-seven Julie Vernon is an intensive-care nurse at one of Melbourne's biggest hospitals. She backs the decision to keep schools open for now.

"A lot of my colleagues have young children, they've got arrangements in place now, and it would be really difficult for them," she says.

"We don't need people to suddenly say, I've got no-one to look after my children, I'm going to have to stay home. That just cuts our numbers. Then you're putting strain on other staff.

"Everyone already is under a lot of stress seeing what's going on and wondering what might happen."

With alarming news of escalating deaths in countries like Italy, and the rising number of confirmed cases in Australia, Mr Smillie is concerned that keeping schools open might only be making matters worse.

The Grange college principal David Smillie. ( ABC News: Margaret Burin )

He is working towards moving The Grange to remote learning.

Just down the road, a private school has already shut down and moved to online learning. But as principal of a relatively disadvantaged school, Mr Smillie knows it's not going to be an easy transition for his community.

Teachers with children may have to look after their own families. Many of his students don't have the internet at home. Some don't have the textbooks.

Dozens of at-risk students will need regular contact and support, especially those in their final year.

"We know we have to deliver 110 per cent to get our kids through VCE."

He's reassuring students and parents that 110 per cent is exactly what his team is giving the job at the moment.

But the current uncertainty is taking its toll.

"We hear that schools aren't closing but we also hear there's a great possibility that down the track that they will. So we're caught, we're asking teachers to manage two things, preparation for the future and the current curriculum program.

"They see it in pretty basic terms that rich schools yet again are safe, when state schools have to bear the brunt of it."