The principal of Kaiapoi High School says the pressure on schools to remain open will be immense without ready access to rapid antigen testing supply.
It follows confirmed Covid-19 cases at multiple North Canterbury schools as the extent of community spread becomes clearer.
Principals at Kaiapoi High School and Amberley Primary have confirmed positive cases of Covid-19 on Monday after six positive cases were confirmed at Rangiora High School at the weekend.
Kaiapoi High School principal Bruce Kearney said he was notified of one positive case on Sunday and expected more.
"Or a smaller self-isolation time, but that RAT test would be even better.
Kearney said without ready access, schools would be likely to close.
"The reality is do you want us to stay open, or not," he said.
"Because as cases grow, the pressure on people to stay at school is going to grow immensely."
The exclusion of schools from the critical worker testing scheme has been largely criticised by the education sector.
The Ministry of Business, Innovation and Employment (MBIE) have said schools may be considered critical where they provided support for critical services by supervising the children of workers unable to have them at home.
"The scheme is not intended to enable the attendance of all staff and students - schools have planned for delivering hybrid learning in a range of scenarios when teachers or students are having to isolate at home," MBIE told RNZ last week.
"This scheme is only for those people who can't have their children at home."
Waimakariri MP Matt Doocey also called for rapid antigen testing to be made available for schools, similar to systems implemented across the Tasman.
He said the developments at Rangiora and Kaiapoi High Schools were "concerning" and highlighted the need for schools to be equipped to respond.
"We should be providing every school with rapid antigen tests to allow twice-weekly testing for all students, teachers and staff – if NSW and Victoria can do it, so can we," he said.
Doocey said classroom ventilation, and the vaccine roll-out for children were other issues the Government needed to urgently prioritse.
Amberley School principal Simon Green confirmed a positive case of Covid-19, a family member of one of the cases at Rangiora High School.
Dozens of pupils had been kept at home today, mostly as a pre-caution, he said.
"We've probably got a quarter of the school away today."
Green said there had been extensive community support for the family who had positive cases and the school was "carrying on as normal".
"We're just trying to keep things as normal as possible," he said.
"I'm looking outside and it's morning tea time...there's kids on rollerblades, kids on scooters, kids climbing trees, it's not the end of the world."
Rangiora High School principal Karen Stewart said, on the school's Facebook page, it had completed a thorough contact tracing process which had identified a number of close contacts.
The school was operating as per normal today but Stewart urged pupils to be vigilant.
"Now more than ever, it is very important that all students wear a mask when indoors and on school buses, and maintain good hygiene practices throughout the day," she said.
A community Facebook page for North Cantabrians was set up on Monday, so the public could remain updated on locations of interest and Covid symptoms.