KUALA LUMPUR (THOMSON REUTERS FOUNDATION) - Boys are more likely than girls to suffer the worst forms of online sexual exploitation, according to a report by Interpol and an advocacy organisation that highlights the largely unreported trend.

Anti-trafficking groups say the global spread of cheap, high-speed Internet, as well as a rise in mobile phone ownership, are fuelling the growth of cybersex trafficking that include children being abused over livestreams and sold for sex.

Although girls account for two-thirds of the victims, the latest study said online images or videos depicting boys, including very young children, often involve more severe abuse, such as sadism and other forms of sexual assault.

The findings were based on an analysis of a database of over one million abuse images and videos from around the globe collected by Interpol, the international police agency.

"It shows just how much we don't know and how much more research need to be done," said Damian Kean of ECPAT International, a Bangkok-based group fighting child sexual exploitation, which jointly conducted the study.

Kean said the findings show a need for countries to take another look at their effort to crack down the crime, and to ensure that help is provided to both girls and boys.

"It may be that the law enforcement doesn't recognise or prioritise it, as they are not aware of the issue and it is under-reported," he told the Thomson Reuters Foundation on Wednesday.

"It is something we need to investigate further."

The Interpol database has identified over 12,000 victims since it was set up in 2009, but authorities are struggling to identify others.

Of those who were unidentified, more than 60 per cent were very young children including infants and toddlers, and one third were boys, according to the study, which was released on Tuesday.

Interpol and ECPAT said victim identification is key to tracking down offenders, because abuse material is often made by those close to the victims, such as teachers and care givers.

"We are speaking about very young children, babies who are just months old, being the victims of extreme sexual assault," the head of Interpol's crime against children unit, Bjorn Sellstrom, said in a statement.