A British charity has said that children in post-conflict areas are being sexually abused by peacekeepers and aid workers.
The abuse involves children as young as six.
After research in Ivory Coast, southern Sudan and Haiti, Save the Children said an international watchdog should be created to deal with the issue.
The charity has called for better reporting mechanisms to deal with what it called 'endemic failures' in responding to reported cases of abuse.
The UN has said it welcomes the report, which it will study closely.
Save the Children said the most shocking aspect of child sex abuse is that most of it goes unreported and unpunished, with children too scared to speak out.
It has criticized the international community for not adhering to the promised policy of zero-tolerance to child sexual abuse.
A UN spokesman, Nick Birnback, said that it was impossible to ensure 'zero incidents' within an organization that has up to 200,000 personnel serving around the world.
"What we can do is get across a message of zero tolerance, which for us means zero complacency when credible allegations are raised and zero impunity when we find that there has been malfeasance that's occurred," he told the BBC.