Claire Lilley, policy adviser at the NSPCC, said she hoped the findings would ring "alarm bells" with authorities that the problem required urgent action.
While more research needs to be done on this problem, we know that technology and easy access to sexual material is warping young people's views of what is 'normal' or acceptable behaviour.
We are treating an increasing number of children who have carried out online grooming, harassment in chatrooms and 'sexting'.
Children who are sexually abusive have often been victims of abuse, harm and trauma themselves. Exposure to this can make them think abusing someone or being sexually violent is ok.
The NSPCC obtained the statistics through Freedom of Information requests to each of the 43 police forces in England and Wales.
But only 34 forces supplied figures - revealing a total of 5,028 offences - so the true number of offences is likely to be higher, the NSPCC said.