BANGKOK (Reuters) - Demand for sex with children is an emerging cause of human trafficking in the Mekong region, the United Nations said on Thursday, as it pointed to a shift in child sex webcam centers from the Philippines to Thailand.

Jeremy Douglas, regional representative of the United Nations Office on Drugs and Crime (UNODC), and Kittipong Kittayarak, Executive Director of the Thailand Institute of Justice, speak to the media during a news conference at the United Nations building in Bangkok, Thailand, August 10, 2017. REUTERS/Amy Sawitta Lefevre

The problem had grown so much that demand for child webcam sex tourism is “outstripping the supply”, Deanna Davy, senior research consultant at the United Nations Office on Drugs and Crime (UNODC), said at the launch of a new trafficking report in Bangkok.

Thailand is a regional hub for the smuggling and trafficking of men, women, and children from poorer neighboring countries such as Cambodia and Myanmar.

Many are forced to work in Thailand’s sex industry and in labor intensive sectors such as fishing, construction, and agriculture, where they are sometimes subject to abuse, according to investigations by rights groups and the media.

Around 4 million migrants live in Thailand, according to 2015 government data. The UNODC estimates that between 4 and 23 percent of migrants in Thailand are trafficking victims.

Jeremy Douglas, regional representative of the UNODC, said recent intelligence showed a shift in child sex abuse webcam centers to Thailand from the Philippines, where authorities have tried to crack down on the illegal trade.

“It used to be the Philippines but through some of our interviews we’ve found that it’s moving here and we’re seeing some intelligence indicate that a move of people setting up operations in Thailand is happening,” Douglas told Reuters.

He said the victims were children from Thailand and neighboring countries.

“When things operate in the shadows like that it’s really hidden ... but this should be an issue of concern,” he said.

A spokesman for the Thai government was not able to comment immediately on the UNODC findings.

The U.N. children’s agency said in a 2016 report poor families in the Philippines were pushing their children into performing live sex online for pedophiles around the globe, calling it a form of “child slavery”.

The UNODC pointed on Thursday to child sex abuse, along with trafficked migrant labor for illegal logging purposes, as emerging trafficking issues of concern in the region.

A Bangkok court convicted dozens of people, including police and politicians, last month for trafficking migrants in Thailand’s biggest human trafficking trial.

In June, the U.S. State Department left Thailand on a Tier 2 Watchlist, just above the lowest ranking of Tier 3, in its annual Trafficking in Persons Report, because it said Thailand did not do enough to tackle human smuggling and trafficking.