"Virtually no country in the world is unaffected by the crime of human trafficking for sexual exploitation or forced labour," the United Nations Office on Drugs and Crime (UNODC) said in its first study on the scale of the phenomenon.
"Efforts to counter trafficking have so far been uncoordinated and inefficient. The lack of systematic reporting by authorities is a real problem. Governments need to try harder," said UNODC director Antonio Maria Costa.
He said it was "extremely difficult" to establish how many victims there were worldwide but added that "the fact that this form of slavery still exists in the 21st century shames us all".
The UN has identified 127 nations, mainly in Asia and Eastern Europe, as sources of trafficking victims, while 137 countries have been identified as human trafficking destinations.
The latter include the European Union, North America, the Gulf states, Israel, Turkey, China and Japan.
A massive 77 per cent of trafficking cases involve women. A substantial 33 per cent involve children and just nine per cent involve men. Sexual exploitation is a factor in 87 per cent of cases and other forms of forced labour in 28 per cent.
The UNODC, which relied solely on public sources of information, stressed the incomplete nature of the data, saying this was mainly due to a lack of cooperation from some governments.
"Efforts to combat trafficking are being hampered by a lack of accurate data, reflecting the unwillingness of some countries to acknowledge that the problem affects them," it said.
The UNODC is calling for improved international cooperation to combat human trafficking and protect its victims.