Two Northland schools went into lockdown yesterday after school staff found an object - initially suspected to be an explosive device, or pipe bomb - on the sports grounds.
Northland Police were called out just before noon after what was believed to be an explosive device had been located on a Whangārei Boys' High School lower rugby field.
Senior Sergeant Patrick Davis said police informed New Zealand Defence Force of the incident.
NZDF advised to lock down both, Boys' High and Whangārei Intermediate, as a precautionary measure.
Police lifted the lockdown by 1pm, but the area around the suspicious object remained cordoned with students being asked to stay clear of the field.
Whangārei Boys' High School Principal Karen Gilbert-Smith was pleased with how students and police handled the incident.
"We practise for these sorts of situations," she said.
"We were very delighted with how the boys handled the situation. Police put student safety at the forefront and have everything under control. We are now back to business as usual."
Whangārei Intermediate sent a message out to parents at 2.15pm saying they were instructed by the police to go into lockdown while officers were investigating.
"The lockdown is now lifted and everyone is safe and accounted for," it said in the email.
Students at both schools appeared calm and could be seen outside of school buildings during the police operation.
A police stab vest was placed over the potentially explosive device and two punch bags put on either side. The device itself could not be seen.
All entrances to the sport grounds remained blocked off throughout the afternoon, diverting pedestrians and cars away from the scene.
Senior Sergeant Davis said police were questioning students and staff, but no arrests had been made as part of the investigation at edition time yesterday.
NZDF dispatched a bomb specialist team from Auckland to help assess the situation.
"The EOD [Explosive Ordnance Disposal team] arrived just before four o'clock at the scene and stood everybody down," Davis said.
The EOD team removed the device and declared the area as safe. The Senior Sergeant confirmed that enquiries were ongoing but no suspect has been named yet.
It is not known whether the object was indeed a functioning explosive device.
Neighbouring Whangārei Girls' High and Whangārei Primary schools were informed about the incident; however their school operations remained uninterrupted.
WBHS issued a statement on Facebook later in the day saying the situation was "well in hand".
"[A]ll our staff and students are accounted for. We do practice for all types of emergencies and we are very proud of the way the whole school has responded.
"The welfare of our staff and students is our absolute priority."
Both schools remained open and classes were running as usual after the lockdown was lifted.