An Upper Hutt high school went into lock-down this afternoon after a teenager was seen walking through the grounds with what appeared to be a pump-action firearm.
Police have since recovered an imitation firearm and students, parents and teachers at Heretaunga College have been allowed to enter and leave the school.
Senior Sergeant Marc Clausen said police received a report that a teenage boy, dressed in a grey hoodie, was carrying a pump-action firearm through the school grounds about 2.40pm.
He said streets around the school were cordoned off while about 20 police staff, including armed officers, and two police dogs searched for him.
Students were told to remain in the classrooms and keep out of sight, away from the windows.