A girl was arrested after allegedly carrying a knife on to Trident High School grounds, prompting the school to go into lockdown for about an hour on Tuesday afternoon.

Police were called to the school about 12.20pm after reports of a fight or altercation.

“There were no injuries reported,” police said.

“A teenage girl was arrested for possession of an offensive weapon and breach of bail.”

Police said the weapon was believed to be a knife. The teenager appeared in Whakatāne Youth Court on Wednesday.

Trident High School principal Mikaere October said the person arrested was a member of the public who came on to the school grounds.

“We had a member of the public who came on to the school site who posed a threat,” he said.

“So, we made the call to go into lockdown as a precaution to make sure everyone was safe. That’s why we have our lockdown procedures.”

The school remained in lockdown from about 12.20pm until 1.20pm while staff ensured the situation had been resolved.

October said the school had recently practiced its lockdown procedures.

He said the incident appeared to be unrelated to the school and stemmed from matters outside the school community.

“Once we knew there was a threat, we went into lockdown. The person wandered through the school grounds, as members of the public sometimes do, moving from classroom to classroom.”

Staff and students had locked themselves in their classrooms.

After police had dealt with the situation, students gathered in the school auditorium before classes resumed.

“We take the safety of our students and staff seriously,” October said.

The incident was unrelated to a series of emailed threats received by schools and other organisations around New Zealand yesterday.

Detective Inspector Glenn Baldwin of Auckland City CIB said police were investigating a number of threatening emails sent to schools and institutions nationwide.

“The Cybercrime Team, supported by staff in other police districts, has initiated an investigation and is working to determine the source of the emails.”

Anyone with information is asked to contact police through 105 online or by phone, or anonymously through Crime Stoppers on 0800 555 111.