The Education Ministry is warning primary schools to be wary of a dangerous "blackout game" being played by youngsters.
The warning comes after an Auckland boy was left unconscious and bleeding after playing the game.
A letter to primary school principals in Northland highlighted the role social media could have in spreading potentially dangerous information among youth, and included contact numbers for schools with concerns about the game or other traumatic events among their pupils, such as recent concerns over a rise in suspected suicides among Northland youth.
The letter said while games such as the one prompting the latest warning had surfaced over the years, there were risks associated with them.
"We recommend that you and your staff remain alert to the potential for students' involvement in the 'blackout game', be mindful about young people's internet and technology use, and are prepared to support them to communicate about things they may be hearing, writing or receiving," said the letter, signed by the ministry's district manager Tim Anderson.