Cases have involved children as young as six. Many games require little verification, and children were so tech savvy they could master steps such as setting up an email account from a very young age.
"You can just sign up and a confirmation email will be sent. But there is no requirement to prove how old you are, or to prove your identity. The only time it really comes into play is if you are on a site where there's a need to input credit card details."
Not every game had a feature where messages could be exchanged, Michael said, but sometimes they can still be used as an introductory point, with communication then happening through other platforms such as email or messenger.
The Oceanz unit can be alerted to cases by local police who field complaints from parents, through Netsafe, international partners, or direct contact through the police website.
It receives two or three reports every week about Kiwi children and teenagers posting sexually explicit images or footage of themselves online, with reports almost always related to material that is self-generated – put up by young people themselves.
Michael said cases involving predators targeting young people through online games were much rarer, but surfaced periodically.
Oceanz was recently made aware of a New Zealand man who was targeting young females who were playing Grand Theft Auto V online, and seeking sexual photos from them.
After an investigation the man was charged and convicted in Wellington District Court in May last year of grooming charges and indecent communication with a person under 16.
Another case involved a victim who met the offender while playing an online game. After that initial meeting the victim was groomed and eventually sent sexually explicit images of themselves.
The offender was based overseas, and NZ Police were able to work with local counterparts to arrange his arrest. He is currently before the court.
A spokesman for Microsoft, which owns both Minecraft and Xbox, said keeping children safe was a priority, and parent controls were offered which help parents choose the content, communication and sharing settings on games.
More information on those controls is available online. Changes include requiring users to have a "gamertag", which allows players to report, block and mute another user. Parents can also adjust settings to block communication from others – a default setting for child accounts.
"We encourage parents to play an active role in their children's online activities by doing three important things - use advanced parental control settings available on devices and gaming platforms, talk with kids about their online activities, and set clear household online rules for their families," the Microsoft spokesman said.
In Australia, a father went to police last year when his six-year-old daughter was exposed to an image of a naked woman when building a virtual hospital as part of the popular Roblox game. Another user may have sent the image, or embedded it in the game she was playing.
And in the United Kingdom a man was jailed for sexually grooming two children he approached through the Minecraft game. There, the charity NSPCC this month released a report pushing for greater Government regulation, and warning that mobile games with a 3+ rating often had the capability for strangers to make contact, something not always clear in the game description and sometimes hidden within games.
Researchers from Swansea University have examined how groomers operate online by looking at words in the recorded logs on convicted paedophiles. They found that most did not pretend to be children when approaching potential victims, and there could be an emphasis on asking a lot of questions to form a bond, such as where a child lives, what they think of a game, and what work their parents do.
Michael, who has headed Oceanz since its establishment in 2009, said parental supervision was crucial. Parents should be checking online "friends", particularly with young children.
"I have talked to parents before who have gone through and done huge culls of the friends list. Because there is only about one or two kids they ever actually knew, and the rest were just these virtual friends and they didn't know who they were."
How to keep your child safe
• If you don't understand it, try it: Explore the games, apps and websites your child uses to improve your knowledge, and take the time to read terms and conditions and options like parental controls. You could ask them to show you how a game works as a way to start a conversation about online safety.
• Set expectations: Talk to your child about the type of behaviours you'd like them to adopt, and what they use the internet for. Technological options like parental controls can help, but should be teamed with online safety education.
• Not everything is as it seems: Sometimes kids won't understand that people are not always who they say they are online. Talk to them about friending or communicating with people they don't know offline. For young children especially, they shouldn't friend someone they don't know personally offline.
Source: Netsafe