Asian crime syndicates behind the multibillion-dollar cyberscam industry are expanding globally, including to South America and Africa, as raids in Southeast Asia fail to contain their activities, the United Nations said in a report on Monday.

Criminal networks that emerged in Southeast Asia in recent years, opening sprawling compounds housing tens of thousands of workers, many trafficked and forced to scam victims around the world, have evolved into a sophisticated global industry, the United Nations Office on Drugs and Crime (UNODC) said.

Even as Southeast Asian governments have intensified a crackdown, syndicates have moved within and beyond the region, the agency said, adding that a "potentially irreversible spillover has taken place... leaving criminal groups free to pick, choose, and move... as needed."