Update The Garda Ombudsman GSOC has launched an inquiry after a garda sub-machine gun was found on the street in Dublin.
The Policing Authority has expressed serious concerns to the Garda Commissioner about the incident.
GSOC says it's conducting a ''public interest inquiry'' following reports that the weapon was found by a member of the public after it fell out of a garda vehicle.
A woman found a bag containing the gun and is believed to have travelled on the Luas and dropped the weapon into Store Street garda station 25 minutes later.
Despite earlier reports, the gun, which was found near garda headquarters at Harcourt Terrace yesterday evening, is not believed to have been loaded.
The commission says it only became aware of the incident through media reports and has not received notification from the gardai themselves.
GSOC says the incident suggests an apparent lack of security and an inquiry is needed to ensure public confidence.
It is now appealing for witnesses to come forward.
Meanwhile, the Policing Authority says the incident is "a very serious issue" and has raised concerns with the Garda Commissioner.
The Authority has also asked garda management for a comprehensive briefing on the force's operating procedures for carrying firearms.
The Minister for Justice, Charlie Flanagan, has said a loaded submachine gun falling out of the back of a Garda car is "a matter of grave concern" to him.
Speaking on RTE Radio One's Today with Miriam, Minister Flanagan said he was informed yesterday about the incident in Dublin.
The Minister said "luckily" any danger was averted as the gun was handed in by a "civic-minded" member of the public to Store Street Garda station yesterday evening.
Mr Flanagan said: "It is a matter of grave concern. Clearly something went wrong, something happened that shouldn't have happened."
The Minister said the incident is now under investigation by a Garda Superintendent and he is looking forward to receiving an early report back.
A community policing group in Dublin’s North Inner City has said it is used to mistakes after a Garda’s loaded submachine gun was found in the area.
The weapon was handed into Store Street Garda station by a member of the public yesterday and an investigation is underway.
The gun is believed to have fallen out of a patrol car driven by the specially trained unit targeting the Kinahan and Hutch gangs.
Marie Metcalf from the Community policing forum for the north inner city said 14 deaths over the past two years is a mistake.
She said: "There's been a lot of major mistakes, there was 14 deaths in this area, so we are used to mistakes or incidents happening.
"Over the past year, with all the deaths we've had, it's been devastating for this community, and I do believe the guards are doing their best."
The Garda Watchdog GSOC says it has not been asked to investigate the incident, as it only investigates incidents involving death or serious injury.
Gardaí are investigating how a loaded submachine gun belonging to one of their units came to be found in the street at around 6pm in Dublin city centre.
It was handed into Store Street Garda Station in Dublin's north inner city by a member of the public yesterday.
It is understood to belong to the armed garda unit that is policing the Hutch-Kinahan gangland feud.
Gardaí say a senior officer "has been appointed to examine all the circumstances" surrounding the discovery.
The gun, a Heckler & Koch MP7 which was in an official bag, is believed to have fallen out of a patrol car driven by the specially trained unit as it went over a ramp and the boot opened.
Sources within the Gardaí told RTÉ that officers in the car saw it happening and a passer-by pick it up.
However, that person had left with the bag and gun by the time the officers had pulled over.
It was handed into Store Street Garda station 25 minutes later and officers do not believe it had been fired as all the ammunition was accounted for.