Forced labor generates illegal profits of at least $150bn (110bn euros) a year, a study by the International Labor Organization (ILO) says, according to BBC News.

The profits are far higher than previous estimates and the ILO wants governments to tackle the problem.Some 21 million people worldwide are in forced labor, it says, with migrant workers most vulnerable. Over half of all forced laborers work in Asia, with 18% in Africa and almost 10% in Latin America.

The BBC says the findings of the new report shocked even the ILO itself.

"This new report takes our understanding of trafficking, forced labor and modern slavery to a new level," ILO Director-General Guy Ryder said.

The ILO found that none of the illegal profits were going into the pockets of the workers, and none of the money was paid as tax revenue.

The group says that two thirds of the huge figure comes from the sex industry, with the rest primarily from domestic work, agriculture and construction. But it admits that much forced labor is controlled by organized crime networks and is very difficult to combat.

In response to its findings, the organization is asking governments to address the root causes of forced labor: poverty, lack of training and job opportunities.

The breakdown of profits

$99 billion - commercial sexual exploitation

$34 billion - construction, manufacturing, mining and utilities

$9 billion - agriculture, including forestry and fishing

$8 billion - private households not paying or underpaying domestic workers held in forced labor