St Peters' School is closed today and there will be no weekend sports after a bomb threat was made.
Students were evacuated from the grounds yesterday.
"Police are investigating the circumstances and are working with the school to ensure the safety of students and staff," a police spokesperson told 1 NEWS.
In a statement on the private school's website announcing its closure today, it says the priority is the safety of students and staff.
"We take this threat seriously and we have activated our response plan.
"Police will have an increased presence on campus along with security guards over the next 24 hours."
The threat comes amid bullying allegations at the school.
WorkSafe is not formally investigating, however it is making inquiries into anonymous bullying allegations at the school.
In a letter to alumni, St Peter's Cambridge confirmed a trust board member was advised by WorkSafe New Zealand that there had been anonymous complaints making concerning allegations about workplace bullying at St Peter's.
Following a meeting with WorkSafe, the school engaged two independent investigators to look into the allegations.
In a letter to parents and caregivers, trust board chair John Erkkila said that he cannot pre-determine the outcome of the investigation.
But if it is deemed that workplace bullying has occurred, he wants the community to know that it will be addressed.
"I cannot and will not allow bullying of any kind in our workplace. Being on the receiving end of bullying behaviour is incredibly damaging to a person’s mental health and it will not tolerated, now or ever."
The private school has not asked the Ministry of Education for assistance in dealing with matters.