Fifty million people around the world are trapped in forced labor or forced marriage, the UN said Monday, warning that their ranks had swelled dramatically in recent years.

The United Nations had set a goal to eradicate all forms of modern slavery by 2030, but instead, the number of people caught up in forced labor or forced marriage ballooned by 10 million between 2016 and 2021, according to a new report.

The study, by the UN's agencies for labor and migration along with the Walk Free Foundation, found that at the end of last year, 28 million people were in forced labor, while 22 million were living in a marriage they had been forced into.

That means nearly one out of every 150 people in the world are caught up in modern forms of slavery, the report said.

"It is shocking that the situation of modern slavery is not improving," Guy Ryder, head of the International Labour Organization (ILO), said in a statement.

"Nothing can justify the persistence of this fundamental abuse of human rights."

'Life sentence'

The Covid-19 pandemic, which worsened conditions and swelled debt levels for many workers, has heightened the risk, the report found.

Coupled with the effects of climate change and armed conflicts, it has contributed to "unprecedented disruption to employment and education, increases in extreme poverty and forced and unsafe migration", compounding the threat, it said.

It is a long-term problem, the report cautioned, with estimates indicating entrapment in forced labor can last years and forced marriage is often "a life sentence".

Women and children are by far the most vulnerable.