Christchurch schools are warned to prepare for a worst case scenario after the deadliest ever armed school attack in US history killed 26 people.
"It's an awful, awful thing to happen [and] you certainly hope it's never going to happen [in New Zealand],'' Mairehau Primary School principal John Bangma said yesterday.
Twenty children and six teachers were gunned down last week at Sandy Hook Elementary School in Connecticut.
Shooter Adam Lanza, 20, entered the school on Friday morning (local time) armed with a rifle and two semi-automatic pistols. Among his victims were eight boys and 12 girls - all aged 6 and 7. He eventually turned a weapon on himself.
Mr Bangma, who is also president of the Canterbury Primary Principals' Association, said his school had gone into lockdown after a gun scare at the nearby Mairehau High School three years ago.
At the time, police cordoned off the schools when gun shots were heard from a nearby property. No one was hurt but two men were arrested.
It was a good opportunity for students to practise how to behave in a lockdown, Mr Bangma said.
"We have practised [lockdowns] a few times.''
Students were warned about the drills in advance to limit anxiety following the earthquakes.
In April this year, Burnside High School went into lockdown after students reported seeing a man armed with a silver pistol on school grounds.
The Armed Offenders Squad was called to the school but the gun was found to be a toy.
In the aftermath of the US tragedy, the New Zealand Secondary Principals' Association warns that local schools need to prepare for a worst-case scenario here.
"I hope that [a school shooting] would never happen but I think we have to be realistic and expect that it probably will and make sure that we do have best placed measures to prevent that from happening,'' association president Patrick Walsh said.
All schools should have an emergency plan in place to deal with an armed intruder incident, he said.
"Most schools now have developed a comprehensive lockdown procedure in their schools.''
When this happens, all classrooms are locked. Students and teachers hide under their desks or huddle in a corner.
The school intercom system is turned on and no one is allowed to leave their classroom until police present themselves at the door.
"Some schools have developed [it] to the point where they now give their building plan to police,'' Mr Walsh said.
"So if there's an armed intruder in the school, the police already have a plan of the whole school.''
School building plans held by the Education Ministry could also be accessed by police in emergency situations, he said.
"I hope we don't get to the point that they have in the United States where you have to hire security guards outside the school and big gates and you check people coming in and out and metal detectors.
"[But], that's the way the world is trending and that's a sad indictment on society.''
Police have also said previously that an armed "shooter" incident was a matter of when, not if, at a New Zealand school.
In a statement, police said: "Police continue to work with individual schools and the Ministry of Education to provide advice on a range of emergency management issues, including potential armed offender incidents.''
Police refused to discuss specific plans for "safety and security reasons".
An Education Ministry spokesman said schools were encouraged to work with "expert agencies" such as the police to develop contingency plans for threatening situations.