Sex offences against children recorded by Gwent Police have gone up by 57% in just one year.
And girls are six times more likely to be targeted, figures from a freedom of information request by the NSPCC reveal.
There were 226 offences recorded in 2013 to 2014 compared to 114 the previous year and experts warned the figures represent just a “fraction” of victims.
The NSPCC say the rise may be down to greater awareness, after high profile historic sex abuse cases, or improved recording methods.
NSPCC head of service for Wales, Des Mannion, said: “These figures are disturbing and clearly illustrate child sexual abuse is a continuing and widespread problem that needs urgent action.
“But we know this is still only a fraction of the true number of victims because some endure an agonising wait of many years before telling anyone – and others never reveal what has happened to them.
“We call on social care services to work to ensure children who suffer abuse receive appropriate support and treatment, so we can close the gap between the needs of children who have been sexually abused and the provision of specialist services they need to help them recover.”
Gwent Police have put the rise down to greater awareness and better recording and said their response to vulnerable children is “constantly improving”, despite the “challenges of operating with a reduced budget“.
Detective Superintendent Ian Roberts, of the Public Protection Unit, said: “High profile cases in the national media have encouraged victims to come forward to report offences that happened during their childhood.
“We have made significant investment with our partners in the statutory and third sectors on our response to identifying and safeguarding children who are vulnerable because they frequently go missing or because they are at risk of sexual exploitation. Again, this has resulted in more offences being reported and investigated.
“We have also changed our crime recording practices which will have made a difference to the number of incidents which are categorised as crime-related.
“We know that offences of this kind are significantly under reported in society and we always anticipated that the changes we have made would result in an increase in police recorded crime.”
Gwent Police and Crime Commissioner Ian Johnston reiterated the thinking that the rise is due to awareness and accurate reporting.
Mr Johnston said: “I want to ensure a victim-centred focus to the services being delivered by Gwent Police and our other partners in the community and what’s important is that there are essential services available to support those who unfortunately become victims.
“This is why I recently launched Connect Gwent, a brand new multi-agency service in Blackwood which aims to make a positive and lasting difference to the lives of all victims.
“This includes New Pathways, an organisation which helps adults and children that have been subjected to sexual abuse and Embrace, the national charity which supports child victims of crime up to the age of 18.
“Victims should be reassured that no matter when a crime was committed we will thoroughly investigate and work with other agencies to provide them with the appropriate help and support they need.”
Some information on the demographics of these offences please.