A teenager has been arrested after a threatening email was sent to Dunedin's Bayfield High School this morning.
Armed police arrived at the school after they were alerted to the threat at 8.17am.
The school went into lockdown and police later escorted about 550 students and staff off the premises.
Acting principal Mike Beagley later said a "managed evacuation" had been carried out.
"Our thanks to all parents and caregivers for their support and help in making this run smoothly."
Detective Senior Sergeant Nik Leigh said police searched a Dunedin house this afternoon and arrested a 16-year-old.
He is due to appear in Dunedin Youth Court on Thursday, facing a charge of threatening to kill.
Leigh said police were working with the school and further charges may be likely.
Mr Beagley said this afternoon that the school received the all-clear to open as normal on Wednesday from police.
An earlier notice sent to parents at 9.30am today said as a precaution the school had been closed for the day and a "managed evacuation" would take place.
Parents were lined up on Musselburgh Rise as groups of students were escorted out of the school.
One parent said she received communication from the school saying there was an email with a bomb threat.
A student who was escorted out said she thought it was just a drill this morning. Students were dispersed in groups into different classrooms. No one was that scared.
"School is in lock down effective immediately. All students on site will be held safely.
"Please keep your son or daughter at home if they have not left for school yet," the school said in a message to parents.
The incident comes almost a year after the school was locked down for two hours last November following an online threat.
Police were making enquiries into a threatening email sent to the school this morning, a spokeswoman said.
"We were alerted to the incident at around 8.17am this morning.
"Police are working to establish the origin of the correspondence."
Cordons were in place and a visible police presence would be in the area while enquiries continued.
