Spot checks in Northern Ireland’s targeting `illegals` on labour market 12 December 2008. Police and members of the Gangmasters Licensing Authority (GLA) have been stopping vehicles in the Portadown, Craigavon and Newry areas on Friday.
It is the first time the authority has used such a tactic since it began work in Northern Ireland earlier this year.
Among the things officers are checking is the standard of vehicles being used to transport migrant workers.
The authority’s Ian Japp said in a recent incident, a number of workers were injured when a vehicle crashed.
"We are trying to raise our profile so that more gangmasters come forward for licensing," he said.
"We are also trying to ensure that those who have come forward are continuing to comply with standards."
During the operation, minibuses transporting workers to farms and factories were pulled over between 0700 and 0900 GMT.
Officials asked workers if they were working for a licensed gangmaster and how they felt they were being treated.
The GLA established offices in Northern Ireland earlier this year with an aim of protecting workers and ensuring employers operate legally.
Offenders face jail sentences of up to 10 years.