Detectives from the PSNI's Organised Crime Branch have rescued 20 potential victims of human trafficking and arrested three men.
This is part of an investigation into labour exploitation which has been running for several days.
The 14 men and six women from Romania were rescued at various stages since last Wednesday at two locations in Co Armagh.
They range in age from 20 to 48.
Police say they have liaised with the UK Human Trafficking Centre and a number of agencies to ensure the victims are safe.
Additional translators have been flown to Northern Ireland from England because of the number of victims involved and the volume of information which needs to be processed.
The three suspects - aged 23, 27 and 31 - were arrested in counties Armagh and Antrim.
They are being questioned at Antrim police station on suspicion of human trafficking, forced labour and slavery, and money laundering.
Two properties have been searched and three vehicles seized.
Detectives have also been liaising with the Gangmasters Licensing Authority as part of their investigation, which is linked to food production.
Police say the operation could continue for some time.