Albany Senior High School in Auckland expects to have to close its doors in the coming weeks due to absences caused by Omicron.
Ahead of the first day of school tomorrow, principal Claire Amos told First Up doors may close again if too many teachers are close contacts.
"We're expecting to hit a point in the next few weeks where we probably close the school down and go full remote, just simply because the teaching won't be sustainable face to face - once we have say more than 10 percent of staff away it's really really tricky."
She said Omicron made things even more difficult.
"Omicron's definitely complex because we're looking at the kind of disruption that's a whole lot messier, you know, because it's a mixture of some students away, some staff away, we're going to hit a threshold where it's going to become unsustainable."
Amos said the school was aiming for "a careful not fearful approach".
She said teaching face to face would not be sustainable if at least 10 percent were working from home and isolating.
Amos said the school can handle absent students, due to Omicron, through online learning.
"Once you have a big number of staff away and say once one of SLT, our Senior Leadership Team are away, that may trigger us actually having to close the school and go full remote for a period of time."
She said that is made easier by having students aged over 14 and the fact that school has a strong digital strategy, but the uncertainty is tough.
Amos said hybrid learning will become crucial this year so teachers and students can do things both online and face-to-face.
She said it was important that staff were able to have a break over the holidays after two years of disruption due to Covid-19.
Potential shortage of relieving teachers
Te Tai Tokerau Principals Association president Pat Newman said there is no indication of teacher numbers at this stage.
Newman said the Ministry of Education has received a large number of homeschooling applications this year and he is uncertain how that will impact on numbers.
"What we do know around staffing is that if we got our normal numbers back and then when teachers start to get ill we have a real problem."
Newman said some Northland schools are still looking to fill staff vacancies but the real problem is that relievers are not available and this is a problem that is affecting a number of places throughout the country.