The game involves stopping the oxygen supply until the player passes out. Two Auckland youths died as a result of playing the same game, prompting a coroner's call for schools to warn children.
Sunset Primary School principal Neils Rasmussen told The Daily Post the incident happened outside school hours.
"We have investigated and we believe this is a storm in a teacup," he said.
The mother of one of the children, who did not want to be identified, said she was shocked to hear her child had been playing such a dangerous game.
She said she had heard of teenagers playing the game to get high.
"Maybe they just don't realise they can die. Life is so precious ... it's not like a video game where you kill someone and they get up a few seconds later. This is real life, not a game."
The school did not hear about the incident until five days later.
Mr Totten said the Ministry of Education had been notified. However, because it happened outside school hours the children will not be disciplined.
"The school grounds are open to the community and the public. To take the matter forward would absolve the parents from their responsibilities."
Mr Totten said he feared raising the issue could cause other children to copy them.
"Personally, I think children engage in behaviour that imitates older children and what they see in the community or on TV or hear about."
He does not think the children realise the possible consequences.
"It's not like video games where you get killed and press the replay button and you come back to life ... You don't want to overreact to it though and giving it some sort of attention or status. It's about keeping it normal and in perspective," he said.
Secondary School Principals' Association president and John Paul College head Patrick Walsh said the issue had been raised nationally among principals.
It was recommended schools talk to students about the dangers of playing such games but it was not that simple, he said.
"I do see some merit in that but things like planking and this choking game, students have a tendency to try things out when they hear about it ... the risk is the kids will start doing it."
Parents needed to ensure they knew what their children watched, Mr Walsh said. If they did not kill themselves, they could be permanently brain damaged or suffer a heart attack or stroke by cutting off their oxygen to get a buzz, he said.
"They think they are bulletproof but they often end up suffering adverse side-effects. The death rate among our teenagers aged 15 to 19 is huge because they are taking these risks ... They have to be told their families and friends could be attending their funeral or it could ruin any future career. We have to get this message through to young people."