A man has told of his fear after four men claiming to be gardai entered his apartment and said they had a warrant to search for drugs.
The incident occurred while Robert Gach (37) was alone in the third-floor flat in Mountjoy Square in Dublin city centre between 5.30pm and 6pm last Friday.
Mr Gach, who is from Hungary but has lived in Dublin for 15 years, told the Herald he answered a knock on his door to discover four large men.
"I was scared. I was alone. First of all they said they were gardai and one of them flashed a badge that I couldn't see properly," he said.
"They didn't even tell me which garda station they came from and they told me that they had a block search warrant.
"There is no such thing as this, I found out yesterday at Mountjoy garda station.
"They didn't touch me, they didn't push me or anything, but they kind of forced their way in.
"They were asking me if I'm smoking weed or something like that and I said that I was not."
The bogus officers asked three times if they could enter Mr Gach's bedroom to search, and they told him to sit down and make a cup of coffee to clam down.
Mr Gach, who is unemployed, said one of them searched in his bedroom for around 10 minutes while the others stayed with him.
Despite the fact that he had a gold necklace and cash in the house, nothing was taken in the bizarre incident.
He described the men as four "big fellows" who looked to be in their 40s. One was wearing a sports jersey, and they all spoke with Dublin accents.
"I was shocked, I've never had a problem with the law before," said Mr Gach.
The imposters wore no garda vests or insignia and had no battering ram with them.
They told Mr Gach they had the right to kick the door in if he did not open it.
He was shown a brief glimpse of the supposed search warrant, but did not get a chance to read it. Gardai at Mountjoy have launched a criminal investigation into the matter.
Impersonating an officer carries a sentence of up to five years in jail. Detectives are now trying to establish a motive for the incident.