The school has close to 800 students.
"It wasn't a decision that was made lightly. We knew that we had to do something and do it fast."
She said she understood the "huge implications" for parents who have had to leave work to collect students.
"We're just so grateful that the community and the parents have responded so well. The overwhelming response has been very supportive."
She said the bug usually lasted for 48 hours and she hoped to have the school re-opened on Monday.
Auckland Regional Public Health Service (ARPHS) said it was working closely with the school to identify the source of the outbreak and prevent anyone else from falling ill.
"ARPHS is taking this outbreak seriously," Medical Officer of Health Dr Michael Hale said.
"It is important to prevent more children getting sick from what is a very unpleasant bug, and we are confident that proper hand hygiene and cleaning of the school will contain the outbreak."
