Northland primary school principals have been warned to be wary of a dangerous "blackout game" being played by youngsters.
The Ministry of Education warning comes after an Auckland boy was left unconscious and bleeding after playing the game.
A letter to local principals highlights the role social media can have in spreading potentially dangerous information amongst youth, and includes 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 have been about over the years, there are 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," the letter, signed by the ministry's district manager Tim Anderson, says.