Stormont Justice Minister David Ford has called for vigilance as the number of human trafficking cases in Northern Ireland more than doubled.
A total of 41 potential victims were identified last year, 2% of all UK cases, the National Crime Agency (NCA) added.
People are used for sexual exploitation, forced labour and domestic servitude.
Mr Ford said: "The scale of human trafficking in Northern Ireland is still relatively low when compared to the rest of the UK.
"That is not to say there is room for complacency. Human trafficking is an abhorrent crime and everyone can play a role in tackling it."
The Department of Justice said: "Victims' may show signs of malnourishment, and appear to be under the control of others."