Schools and universities across New Zealand are about to shut due to coronavirus.

Prime Minister Jacinda Ardern on Monday raised New Zealand's alert to level three with the most extreme level, four, coming in after 48 hours.

Schools across New Zealand will be closed from tomorrow, except to the children of essential workers such as doctors, nurses, ambulance drivers and police. This will be temporary, and schools will close entirely from midnight Wednesday.

Education Minister Chris Hipkins announced all universities should close as soon as possible.

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Victoria University of Wellington confirmed via Twitter it would be shutting as soon as possible. AUT university in Auckland said all teaching an assessments would be suspended for one week.

Secondary teachers union PPTA earlier called for physical schools to shut but only when systems were in place to ensure continued education.

Raumati Beach School principal Mike Farrelly, said he felt a huge relief at the announcement.

TOM LEE/STUFF Education Minister Chris Hipkins said the government was ready to act if needed.

Farrelly, also President of the Wellington Regional Primary Principals' Association, said about 300 of his 600-odd students had been kept home on Monday.

"I think it is the right decision for everybody," he said.

"It was always going to be a hard decision.

"It gives us that certainty moving forward.

"It takes that angst away from staff and students and the community.

"We have our learning at home programme all ready to go."

About 10 teachers and teachers' aides had also not come in - often because they had elderly or immuno-compromised relatives at home who they didn't want to pass the virus on to.

Clyde Quay School principal Liz Patara earlier said it wouldn't be long till "I can't staff the school".

In an open letter to Ardern on Monday morning, Teaching Council chief executive Lesley Hoskin made the call to close all schools and day cares immediately, which she said was on behalf of 130,000 teachers.

"As the voice of teachers, the council, on behalf of all teachers, implores you to act now and to move to Alert Level Four, closing early childhood centres and schools.

MAARTEN HOLL/STUFF Mark Potter, principal at Berhampore School, said guidance so-far had been good.

Prior to Ardern's announcement Post Primary Teachers' Association President Jack Boyle said his union – representing secondary teachers – had written to the Prime Minister, urging her to immediately direct schools to provide teaching and learning at home.

Schooling from home should happen but shouldn't happen without systems in place to ensure children could still learn, he said.

Wellington father Seth Campbell imagined his sons would be looking forward to some time at home.

He and his wife both had flexible working arrangements – meaning childcare for Wilder, 9, and Silas, 11, wasn't an issue.

But the announcement would mean an adjustment to a new routine, he said.

"It is a real test, a total paradigm shift," he said.

Shane Buckner, principal of Christchurch's Wairakei School and president of Canterbury Primary Principals' Association, said although it was short notice, it was "definitely" the right decision to close schools.

"I think the two-day turnaround that we've got until we become Level Four is really important to help essential services," he said.

There was not currently a list of that schools would remain open for the children of essential service workers but it would be up to individual schools, he said.

"I have got three or four children that we will be looking after over the next couple of days. It will be two or three staff from each of the schools, I imagine."

Christchurch mum Sacha Sayers said believed the shut down was the right decision.

"My kids have been worried about the situation as the news only has the doom of death, not the survival rate."

Sayers, who has three children at intermediate and high school, said she was lucky because she could work from home, and her children were old enough to look after each other even if she was not able to work from home.

Chris McKeen A parent at Ponsonby Primary School in Herne Bay, Auckland has tested positive for the coronavirus.