Some Papatoetoe High School students have made the "conscious choice" not to get tested and instead stay at home and self-isolate.
Principal Vaughan Couillault told the AM Show that students who had opted not to get tested need to inform the school what they're doing and if they're staying at home, "stay at home".
Couillault was now hopeful his school could return to normal this week after three new cases emerged yesterday, one of which was a student from the school.
The remaining two were siblings of the student, it was announced yesterday.
The schoolgirl was identified as a casual plus contact of the first student at Papatoetoe High who tested positive who was linked to the Valentine's Day outbreak but had not returned to the school and had been isolating at home.
Dr Ashley Bloomfield told the AM Show the student wasn't in the same class as the original case so the infection must have occurred while passing in a hallway or some other area of the school.
When asked whether he would prefer the school just to shut for two weeks, Couillault said that wasn't an option as that would mean losing 20 per cent of the school term.
"Nah, actually I would probably prefer if everyone got tested and we got stuck into school learning within 48 hours," he told the AM Show.
"I don't want to lose 14 days' worth of learning. I can take another couple of days but another 14 days, that's really hard to catch up on.
"That's 20 per cent of the term, that's a big hit."
Couillault said he couldn't explain why the last 11 students "were a bit slow" in getting tested as it could have been a myriad of reasons.
"I can't explain why we're a bit slow on it because there's all manner of reasons why people do or don't comply with requests like that.
"In some cases, there's a number of cases where it's a conscious choice and they're choosing to isolate for that 14-day period.
"For some, a cellphone number has changed or something like that. We've got quite a dynamic contact list in our community and often there's quite a lot of change to that that we're not notified about and in situations like this where really hard cases come to the surface just when you don't want them to."
He said he would urge all students to co-operate with health authorities and get tested.
"Moving forward that is what we're asking for, so if you haven't co-operated up until now and communicated because you're allowed to make that conscious decision to self-isolate that's all good but we need to know what's happening, what's going on and if you're being asked to stay home and self isolate then stay at home and isolate until you've got that test done.
"It's common sense, really."
By the time the school testing centre closed yesterday, close to 700 people had been through.
He told the Herald yesterday how proud he was of his staff who handed out water and music teachers who put on an impromptu concert for those waiting in line.
He also praised the students who stayed late to get their test done.
"It's epic. Students at 3.15pm were able to leave if they needed to or wanted to, but a whole lot of kids stayed in the queue," he said.
"The music teachers put on a music concert for the students. It was a really cool vibe."
Asked if he was proud of the students, he said he had the best job in the world.
"There was a real sense of community, and yes a little bit of anxiety, but [also] quiet confidence that we will get through it, that there is light at the end of the tunnel."'
Staff and students and the people they live with have been told to stay at home and isolate until that staff member or student returns a negative test.
Once that person returns a negative test, the unit can then return to normal daily life.
Couillault said parents were staying home from work and siblings that go to other schools also kept away from the classroom.
"I would suggest that for many families, that's incredibly burdensome and that they are doing it tough," he said.
There are 1400 students at the school which equates to around 800-900 families.
"Most of our families have a number of people living in their household."