Further tests are being carried out at Kaipara College, including in classrooms, after asbestos was found in the school hall, forcing the school's closure.
Kim Shannon, head of education infrastructure service at the Ministry of Education, says further tests are being carried out during the weekend after initial results showed some asbestos present in dust swabs from the school hall and administration block.
"The material has come from the roof of the hall, which is an older building. We are fencing off the affected parts of these buildings to ensure they remain isolated," she said.
Once the further test results have come back, the ministry will work with the school to either reopen, if it's safe to do so, or to accommodate students at nearby schools.
"We offered Kaipara College the option of relocating on Monday and Tuesday and to provide transport for students and staff to do that. But they have decided to hold off on that option until the results of the further tests come back," Ms Shannon said.
The principal and board of trustees of the Helensville-based school have decided to keep the school closed on Monday and Tuesday.
WorkSafe New Zealand and the Auckland Regional Public Health Service have been notified.
On Friday, principal John Grant said the health and safety of staff and students was of paramount importance.
The asbestos dust was found during routine weather-tightness testing.