With widespread poverty, lax laws, and creaking judicial systems, Thailand, Cambodia, Vietnam, Laos, and the Philippines have long been seen as soft spots by foreign and local pedophiles seeking out underage sex in person, AFP reported.
Tougher policing and greater awareness has deterred some offenders, but technology has shifted the patterns of abuse in a region with growing access to broadband Internet and encrypted technology.
Pedophiles can now use an array of mobile and online tools — including social networks, video-sharing sites, and the dark web — to direct and watch child rape and sexual abuse with anonymity, experts warned.
"Predators watch the rapes on large platforms that are not likely to close," said François Xavier Souchet, of Thai-based NGO Terre des Hommes.
"It's live, nothing is recorded... everything is encrypted. They pay more and more in Bitcoins, encrypted money makes their transactions as secure as possible," he added.
This week online giants including Apple, Google, Microsoft, and Facebook are giving evidence to the independent inquiry into child sexual abuse (IICSA), which is being held in London and will look at how to prevent online sex crimes as part of its remit.
In March, a teacher was arrested and charged in his native France with rape, abuse of minors and possession of child pornography.
The 51-year-old, who worked in schools in Asia, is alleged to have befriended kids in a working-class Bangkok neighborhood before building a rapport on social networks, police sources told AFP.
The same month, prosecutors charged another Frenchman with ordering videos of rape and sexual assaults of Filipino children.
The suspect, a 55-year-old former police officer, was arrested after a seizure of computers and livestreaming equipment in the Philippines.
In late April, former British Army officer Andrew Whiddett, 70, was found guilty by a London court of spending thousands of pounds paying for livestreamed sexual abuse of children from the Philippines.
The National Crime Agency (NCA) estimates 80,000 people in the UK present some kind of sexual threat to children online.
The cyber-abuse phenomenon is reaching "Cambodia and Vietnam", warned Damian Kean, of the Thai-based NGO ECPAT, which specializes in combating the sexual exploitation of children.
In hyper-connected Vietnam, foreign pedophiles are increasingly targeting young victims online, often on social media.
The communist state last year instated harsher penalties to combat the crime — anyone guilty of molesting a child under 16 faces 12 years in prison, while child rape comes with a maximum sentence of death.
But catching a pedophile requires help from the communities within which they operate - communities which are often marginalized, poor and mistrustful.
Souchet of Terre des Hommes explained, "Particularly ethnic minority communities across the region do not trust local authorities."