A US mum is demanding answers after her seven-year-old daughter's virtual avatar in the hugely popular game Roblox was "gang raped".

Amber Petersen from North Carolina is now urging parents to delete the gaming app after witnessing the confronting sight.

Ms Petersen said she was reading a book to her daughter as she played the game on her iPad when she saw what was happening.

"My sweet and innocent daughter’s avatar was being VIOLENTLY GANG-RAPED ON A PLAYGROUND by two males," she wrote on Facebook.

"Words cannot describe the shock, disgust, and guilt that I am feeling right now, but I’m trying to put those feelings aside so I can get this warning out to others as soon as possible."

A screenshot from the Roblox game. (Amber Petersen) (Amber Petersen)

In the game, the girl's avatar was pinned down by two male characters and one female avatar who appeared to be scantily clad.

"I had to talk to her about rape," Ms Petersen told WRAL.

"I had to talk to her about consent. She's seven. I was not ready to have that conversation with her."

One of the male characters had what appeared to be an erect penis.

The offending images have been blurred by nine.com.au, but were unpixellated in the game.

A censored screenshot from the Roblox game. (Amber Petersen) (Amber Petersen)

Ms Petersen implored parents and caregivers to delete the app and put away children's screens.

"Books cannot be hacked, but sadly, I’ve learned the hard way that a child’s innocence can be just at the touch of a button," she said.

Roblox released an official statement condemning what happened.

"We were outraged to learn that Roblox's community policies and Rules of Conduct were subverted," the company said.

"We have identified how this bad actor created the offending action and are putting additional safeguards in place to reduce the possibility of this happening again in the future.

"In addition, the offender was identified and has been permanently banned from the platform and we have suspended the game. We have zero tolerance for this behaviour."

The online platform allows users to create their own games for others to play, which is how Ms Petersen's daughter ended up in that confronting situation.

Another North Carolina mother, Britney Shinall, wrote on Facebook that she discovered her little boy playing a game on Roblox where the goal was to commit suicide.

"My son has not been allowed to play this since I walked into him playing and the mission was to kill yourself," Ms Shinall said.

"Like he had to go around his characters house and drink bleach or find a knife."