First day on the job nerves caused a Protective Services Officer to accidentally fire a gun inside Victoria Police's headquarters in Melbourne.
Assistant Commissioner Chris O'Neill said the officer incorrectly removed a name identification tag on the weapon which caused it to fire inside the police armoury.
''The PSO on his first day, obviously with some nerves as we all would be on our first day, has failed to remove this ID tag, which is only on it until the firearm issued, so it's one of those things when you obviously only do it once,'' Assistant Commissioner O'Neill said.
''He's loaded the firearm in the correct manner placed it in his holster ... [but] upon removing that name tag the trigger has been pulled and the firearm has been discharged.''
Assistant Commissioner O'Neill said the incident wasn't a reflection on the aptitude of PSOs or their training and was confident nerves wouldn't get the better of the PSO and a similar incident happen on a train platform.
''Victoria Police has great training. Police and PSOs go through the same firearm training. This has happened on day one, when I'd say the PSO would be a bit nervous on day one.
''It is very unfortunate. It doesn't happen often. We have been issuing thousands of these firearms, they're the same firearms the police get. We now have 192 PSOs who have these firearms and this is the first instance this has happened.
''We'll put systems in place to make sure this doesn't happen again.''
A Victoria Police spokeswoman said the officer fired the shot accidentally, and the bullet hit the floor.
''No one was injured and no members of the public were present,'' the spokeswoman said.
Detectives from the transit criminal investigation unit are investigating the shooting, with oversight from the Ethical Standards Department.
Protective Services Officers are armed with semi-automatic firearms, capsicum spray and batons and complete 12 weeks of training also given to police cadets, including the same three weeks of weapons training.
The officers, who are overseen by police, have the power to arrest and detain offenders in the vicinity of a train station until police arrive, and pursue offenders out of a station or onto a train.
They can also be deployed as a large-scale rapid response team if ordered by police.
The Baillieu government aims to have 940 Protective Services Officers patrolling Melbourne and selected regional railway stations by 2014.
Police Association secretary Greg Davies criticised Assistant Commissioner O'Neill for indicating that first day nerves caused the misfire.
Mr Davies said it was too early to apportion blame, otherwise ''what's the point of having an inquiry''.
''From my understanding I don't know if it was first day nerves,'' Mr Davies said.
''I think it's premature and speculative to be putting out a reason for why people think it happened.
''There's going to be an inquiry by the Ethical Standards Department. They'll determine the facts and the circumstances of what occurred and no doubt someone will make a recommendation to the Chief Commissioner.''
Michelle McDonnell, a spokeswoman for Your Rights on Track, called for guns to be taken off PSOs for the safety of the community.
Your Rights on Track is a coalition of legal community groups concerned about the safety risks posed by PSOs, particularly for vulnerable people.
''While safety on train stations is vital, we think a better option would be to remove PSOs' guns,'' Ms McDonnell said.
Premier Ted Baillieu said PSOs were trained exactly the same way as police officers in relation to firearms.
"None of us were there. This does happen from time to time," Mr Baillieu said of the accidental shooting.
"It has happened before with Victoria Police. The important thing is that Ethical Standards [Department] investigate this and make sure it doesn't happen again."
- FFX Aus