Gardaí are examining complaints that immigrants have been scammed out of thousands of euro by fake lawyers purporting to offer advice on visas, work permits and deportation matters.
Several complaints received by the legal regulator have been referred to gardaí in recent months amid concern deception offences have been committed.
Legal Services Regulatory Authority (LSRA) chief executive Brian Doherty said that in most cases the services complained of were advertised on Facebook.
He told the Irish Independent the LSRA was concerned at the "clear targeting of vulnerable immigrants" after hearing some "heartbreaking" accounts.
"What we have seen are instances where a firm uses social media to advertise legal services in relation to immigration, promises successful resolutions to issues and in some instances purports to be a legal practitioner," said Mr Doherty.
He said people seeking permission to stay in Ireland and work permits had complained of being duped.
"The complainants have reported paying up to €3,000 for assistance and then no real assistance is provided," he said.
Around a dozen complaints and contacts on the issue have been received by the LSRA since last October.
As the authority can investigate only genuine legal practitioners, it has acted as a conduit for such complaints to be made to gardaí and provided assistance to detectives.
Mr Doherty said the authority had been trying to get the message out that immigrants needed to be vigilant.
"We have posters up in local authority buildings, emergency accommodation and direct provision centres in a number of languages," he said.
"We are trying to warn those people that might be availing of these services that if someone purports to be a legal practitioner that they can check the roll of practising barristers that we maintain or the roll of practicing solicitors maintained by the Law Society.
"Should they subsequently then have a complaint to bring to us, we will see how we can assist them."
Earlier this year, the Law Society issued a warning about two would-be immigration law practices, one offering services in Cork and the other in Dublin.
It said neither of these were authorised or regulated. The society also said a person associated with these practices was not on the roll of solicitors.