Ward said while he was "highly conscious" of the effects this decision would have on students and whānau, he did not have any other choice.
"This has always been a last resort but we had just had to make the call this week," he said.
"We have tried everything else like doubling up classes and putting teacher aides in. And, unfortunately, this is where we have got to."
It was the first time the school has ever had to roster students home due to illness circulating, he said.
"It hasn't hit us before this badly.
"We have tried to avoid it - this isn't something we ever want to do and we know it has an impact on our community."
He said the decision to keep senior students at school was made as preliminary exams were fast-approaching.
Work was not being set for the students rostered home, however they had been asked to complete homework.