Irish police have been left red faced – after $12,000 in cash seized from thieves went missing from a bag of evidence.

The discovery was made at Balbriggan police station after officers thwarted a $40,000 raid on a local post office.

Armed robbers made off with the cash but were stopped in their tracks by detectives who recovered the money.

Now police have discovered that $12,000 is missing from the bag containing the cash.

Forensic officers have begun examining the bag to determine whether it was cut open according to the Irish Independent.

The paper reports that the cash was seized when detectives on an anti-crime patrol responded to an emergency call about the raid.

They intercepted the gang as they were making their escape and the cash was taken to Balbriggan station in north Dublin where it was bagged and tagged after being photographed for use as evidence in a subsequent criminal trial.

The paper says the money was then placed in a safe at the station.

The report adds that when the owner of the premises called to seek the return of the money, officers discovered a small tear in the side of the bag.

When the contents of the bag were checked, it was discovered that some $12,000 had disappeared.

Forensic officers were called and a thorough search of the station was carried out. All officers who handled the money were interviewed but none of the missing cash has been traced.

A senior officer from outside the division has been appointed to head a formal investigation into the disappearance of the cash.

An elderly man in Cork was convicted and fined on MondayGoogle Images