A lockdown at South Wellington Intermediate School has now been lifted after police responded to an incident.
Initially, police said they had received an unconfirmed report of an incident near the school in Berhampore, but did not say what type of incident it was.
They said the school and several neighbouring premises were locked-down as a precaution.
The school later posted on its Facebook page that the lockdown had been lifted and students were being sent home as normal.
In a post addressed to parents and whānau, principal Toby Stokes said a person with a weapon was seen near the school just before 3pm.
The school followed emergency procedures after getting advice from police, Stokes said.
He said he was proud of the "fantastic response" and everyone had acted sensibly.
Police said they found an airgun and were speaking to a youth about the incident.