A POPULAR online gaming platform for children has been branded a "paedophile's gateway" after Aussie kids received sexually-charged messages as they played.
Roblox, hailed as the "new Minecraft", hosts more than 15 million user-created games that lets players chat with each other.
Perth mum Kayla Bailey said she checked her nine-year-old daughter's chats one night and was shocked at what she saw.
"Someone had said, 'where were you all weekend?'
And she said, 'I told you I was at my dad's house'.
And he said, 'I bet you weren't and were up all night sucking d**k'.
She said, 'No I was at my dad's!" Ms Bailey told 9news.com.au.
She continued: "To be honest I can't even really remember the rest of the conversation because I lost my marbles over it and deleted it. I had to calm down to talk to my daughter about how inappropriate people could be on the other side of the game and that stranger danger is so real,even on computers."
Sydney mother Shannon Mitchell shared a similar horror story. She said the alarm was raised when her 10-year-old daughter suddenly began using vulgar language.
"It was things like, 'I want to put my penis in your vagina. I want to lick your p***y. I want to sleep with you'," she said.
"I said to her, 'where are you getting this from?' After a while she admitted to me it was Roblox."
She said her daughter had told the person she was chatting with her age.
"It just blew my mind. I know these grubs are out there but you just don't think it's going to happen to your child," Ms Mitchell said.
Roblox spokesman Brian Jaquet said community safety was the company's "top priority".
He said safeguards included parental controls to shut-off chat capability, age "visibility", and specific word restrictions in chats involving children under 13.
"Together we want to work with parents and the community to stay vigilant over today's online landscape and continue to build best practices to avoid negative situations," Mr Jaquet said.
"We want to make sure that all users are aware of the potential challenges and navigate them through it."
Jayne Crossling, the Acting National Co-ordinator Missing Persons and Exploited Children for the Australian Federal Police, said child sex offenders often use the "privacy and anonymity of the internet to identify and target vulnerable children".
She said parents should take screenshots of the chat and user's profile, before blocking them and contacting police.
Update your news preferences and get the latest news delivered to your inbox.