Gardaí are investigating allegations that a nurse at Peamount Hospital in west Dublin threatened to ill-treat a patient.
A spokesman for the hospital said last night that a member of staff had been suspended pending an inquiry.
He said that an internal and external investigation was under way.
The hospital declined to comment on the nature of the allegations or to confirm that the member of staff involved was a nurse.
However, informed sources said the investigations involved a nurse, who was alleged to have threatened to ill-treat a patient.
Garda sources said last night that an official investigation had commenced and that statements had been taken. However, they said the inquiry was at an early stage.
A spokesperson for Peamount said the allegations were "serious".
It is understood that it was the hospital authorities who notified the Garda of the allegations.
Peamount Hospital, located in Newcastle in west Dublin, deals with respiratory cases and young people who are chronically ill.