Christchurch's Hillmorton High School has been forced to close for two days because rodents have damaged a fibre cable and the internet is down.
Student were asked to work from home on Monday and Tuesday while repairs were done at the school.
In a school newsletter, principal Sam Ainsworth said staff discovered the problem on Monday morning.
"Unfortunately, we have a cabling issue with a core fibre cable connection that has been severely damaged by rodents over the weekend. This fibre connection is our main connection to the school and as a result of the damage, I have concerns about managing the health and safety of large numbers of students," he said.
"While I know that this will not be a popular decision for all and may be challenging for many families, it is a decision we have not taken lightly."
The school's servers were down and there was no Wifi network or phone system, he said.
Ainsworth told RNZ a cabling company had spent the day working on a temporary fix.
"We've managed to get some systems back online and we can open for around 500 students tomorrow, so our Year 7's, 8's and 9's. It will be pretty much an offline learning day tomorrow but there's enough structures in place we can now open safely for those kids and staff and then we'll welcome the whole school back on Thursday," he said.
"We do have security online now, our alarm system is back up and running.
"We didn't know that something like this would be possible, we've never had anything like this happen before. It's a bit of a shock to all of us certainly the physical aspect of the incident itself. I think it's pretty rare across schools and institutions."
The Ministry of Education said its property adviser was in contact with the school.


