Rotorua primary school principals are increasingly concerned about the video game Fortnite as it affects some pupils' school work.
The game was first released in 2017 and it's estimated there are 125 million players worldwide. The online multi-player game can be played on Playstation, Xbox and on smartphone.
In Westbrook School's most recent school newsletter principal Colin Watkins said the school was becoming "increasingly aware of and concerned" about children playing the game.
"This game is recommended for those 12 years and older and seems to be extremely addictive. Many children are staying up late and spending many hours on the game each night.
"They are also bringing problems or issues that arise back into school the next day. We have definitely noticed changes in behaviour and energy levels at school of children who play the game regularly."
Watkins asked parents to be aware of what children were doing on the internet and consider a time limit and a balance with outdoor play and face to face interaction.
Otonga Rd Primary School principal Linda Woon said she shared Watkins' concerns and had issued a statement about it in an August school newsletter.
"The reason for an age rating is to protect children from being exposed to content and violence levels beyond what they can deal with.
"Sometimes games look harmless because they are in cartoon format but don't be fooled by this. Please monitor what your children are doing and what sites they are visiting when they are on a device."
Woon told the Rotorua Daily Post schools were in a tricky situation.
"We are using more and more technology and online sources for our classroom learning - while at the same time being cognisant of the amount of daily screen time being limited.
"It must be very hard for parents to strike the balance."
Woon said adults needed to lead by example when it came to screen time.
Rotorua Daily Post Facebook page users said it wasn't just children who played excessively while one said she had rules about when her children could play the game and for how long.
What is Fortnite?
- Multi-player online shooting game first released in 2017.
- Last man standing wins.
- Players must find and arm themselves with weapons like rifles, traps and grenades as well as materials to build structures.
- Free but players can buy outfits and bonus passes.
- Cartoon design with no bloodshed.