School principal Michael Earl said online everyone involved did "extremely well" and followed instructions.
Earl says everyone is safe and accounted for, with a notice going out to parents tonight with more information about the lockdown procedures.
A spokesman for the police says they were notified of a man acting suspiciously on Sudeley St, next to the school in Ōrakei after midday.
"Information received by police suggested the man had made threats he was carrying a firearm," he said.
"As a precaution, nearby Ōrakei School was placed into lockdown, which ended up being for a very short period of time. Police attended the area and located the man.
"Police have spoken with this man and we have established that he was not in possession of a firearm."
The man was taken into custody and is assisting police with their inquiries.
Kelston Boys High School, Kelston Girls College, Kelston Intermediate School, and St Leonards Rd School went into lockdown on Tuesday afternoon.
"Police initially had information that there were concerns for a person's welfare near Kelston and a firearm may have been involved," Acting Area Commander for Waitematā West Inspector John Thornley says.
"Police located the subject of this report, a BB gun has been located and the matter has been referred to Youth Aid.
