The Criminal Assets Bureau has discovered a new form of fraud that has become popular since the recession started, the Oireachtas Finance Committee has been told.
Detective Chief Superintendent John O'Mahony said the CAB calls this the 'builder bailout' fraud.
He said the fraud involves creating a false identity for a person, who then gets a mortgage on one of the builder's properties.
The result is the builder gets paid for a property, which he had been unable to sell and the accomplice gets a percentage of the deal.
He said criminals had also used mortgages as a way of hiding the proceeds of crime.
Criminals would repay a loan with large cash lodgements before selling the property and the price they got appeared to be what he called clean money.