The Minister for Justice, Mr O'Donoghue, has described as a "fairy tale" claims that people who have stolen goods give them back "willingly" to Sinn Fein.
Speaking at the Humbert School, he said there was no place for vigilantism in Irish society "no matter how it is dressed up".
He was asked about posters being put up by Sinn Fein about crime in north Kerry. "It is true that claims are made by Mr [Martin] Ferris that he gives stolen goods back to people and that once he explains to people they should give them back they willingly do so. It is a rather unique fairy tale."
He said the Republic was a democracy, and parties were free to put up posters, but it was not acceptable where they sought to usurp the powers of the Garda Siochana.
He said it was often difficult to get the evidence and it was rare for people, after they returned goods, to say they were intimidated.
Mr O'Donoghue added that vigilantism was not widespread in north Kerry. However, he believed that "constant repetition of our revulsion for this" would eventually get the message home.
Democracy could be damaged by the actions of persons or groups who jumped on populist bandwagons to gain short-term advantage.
It was completely intolerable for any person or group of persons to seek to usurp the functions of An Garda Siochana in the investigation of crime.
Individuals or groups who sought to usurp the functions of the Garda or who engaged in intimidation, assaults or threats were the opponents of democracy and should face the full rigours of the law.
