Police have searched hospitals and schools across the country after threats were made against a number of organisations.
They have searched Wellington and Bowen Hospital in the capital and Burwood Hospital in Christchurch. RNZ understands police have also been at Auckland City Hospital.
However, Te Whatu Ora is reassuring people it is safe to attend hospitals as usual.
The Ministry of Education confirmed Auckland's Saint Kentigern College was evacuated as a result of the threatening email.
It would not reopen until police have given clearance.
Spokesperson Isabel Evans said they understood the anxiety incidents such as these caused for school communities and ministry offices were open for schools which needed assistance.
Late this afternoon the ministry said it was aware of only one school that received an email threat today.
Evans said St Kentigern College was the only one it knew of to receive an emailed threat.
Some students were sitting NCEA exams at the time, she said.
NZQA has confirmed around 170 students at St Kentigern were meant to sit exams today and may be impacted by the school's evacuation.
Deputy chief executive Jann Marshall said the impact on students will differ depending on the individual but all will be able to apply for derived grades.
She said other Auckland schools accommodated some Saint Kentigern students to sit exams this afternoon.
Those students will be awarded the better of the grade they received in the exam and the derived grade supplied by the school.
The safety of students and staff was a top priority, she said.
"Each school has its own processes for handling a security lockdown, and these apply during the exam period.
"Students who are unable to sit an exam, or whose performance is impaired because of a security incident, can apply for a derived grade, or their school may apply for derived grades at scale to apply."
PPTA acting president Chris Abercrombie said the primary concern of schools would be ensuring the safety of staff and students.
Police said staff were working with those impacted and would respond based on individual circumstances.
"Police acknowledge how unsettling these emails are for all concerned. We'd like to thank all involved for their cooperation as we investigate these emails."
Te Whatu Ora's national director for hospital and specialist services Fionnagh Dougan confirmed some hospitals received an "email of concern" earlier today.
"[It] was immediately referred to police for further investigation," she said.
"Staff have followed police advice and we are remaining vigilant. Our hospital sites have remained open and all services are continuing.
"Members of the public with appointments at our hospitals or needing emergency treatment should be assured it is safe to attend their local hospital as usual."
Bowen Hospital in Wellington received an email about an unconfirmed threat at 9.30am.
The private hospital's management took the threat as serious and enacted safety protocols.
In a statement, chief operations officer Stephen Johnston said police were immediately informed.
He said that once on-site, officers did a thorough sweep of the hospital.
Johnston said police have confirmed Bowen Hospital is safe.
Medical procedures and any disruptions to patients and staff were avoided, he said.
EAP support is being offered to Bowen Hospital staff impacted by the threat scare.
On 26 July 2022, some North Island schools went into lockdown and moved students off site after receiving phone threats.
Threats were made to five schools in Waikato, Thames Coromandel and Gisborne districts, police said.
No specific risk was ever found.
The next day, bomb threats were made to four schools and at least a dozen the next, causing widespread disruption with many of the schools having to evacuate.
The Principals' Federation said those threats originated from an overseas cyberbot.