Green Bay High School in West Auckland is the eighth school to be linked to the current Delta outbreak, which has now grown to more than 100 cases.
The West Auckland school confirmed the positive case via its Facebook page.
"We found out this afternoon that we have a GBHS student who has tested positive for Covid-19," the post said.
The Green Bay High School case takes the total number of schools with confirmed Covid-19 cases as a result of the latest Delta outbreak to eight.
Attached to the Facebook post was a letter from the Auckland Regional Public Health Service (ARPHS).