Asbestos-hit Kaipara College will remain closed all week, causing disruptions for senior students facing imminent exams.
The Helensville college, which has 650 students, has been closed since Friday after routine tests of water-tightness found asbestos dust in the school hall and administration building.
Principal John Grant said tests across the whole school over the past few days had so far come back negative.
He said they're pulling together local sports clubs and other facilities for senior students to be tutored at in the meantime.
The Ministry of Education said it will be contacting all schools to remind them of the importance of maintaining their buildings.