After allegations of brutality and the sacking of a top officer earlier this year, Victoria Police has been rocked by revelations more than 258,000 breath tests were faked.

An external investigator will be brought in to examine the falsified tests, in which officers blew into RBT straws themselves or placed fingers over the holes.

The fake tests were discovered just weeks after the force was hit with allegations of excessive violence, with the beating of a disability pensioner caught on camera.

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After allegations of brutality and the sacking of a top officer earlier this year, Victoria Police has been rocked by revelations more than 258,000 breath tests were faked (stock image)

An external investigator will be brought in to examine the falsified tests, in which officers blew into RBT straws themselves or placed fingers over the holes (pictured is an arrest caught on camera)

The fake tests were discovered just weeks after the force was hit with allegations of excessive violence, with the beating of a disability pensioner caught on camera (pictured is an incident at Bendigo Police Station)

The incident involving six officers allegedly beating the mental health patient with batons, verbally abusing and pepper spraying him was caught on camera.

Police were referred to oversight body Independent Broad-based Anti-Corruption Commission (IBAC) over the incident.

The arrest of a Sudanese-born Melbourne man who allegedly robbed and trashed a chemist in 2016 was also reported to the IBAC.

Footage showed the man being punched 11 times and hit with a baton before one of the officers stomped on his back in a two-and-a-half minute ordeal.

The allegations of brutality followed the resignation of Assistant Commissioner Brett Guerin (pictured) over a series of offensive online posts made under a pseudonym

That incident followed a complaint by Jia Meeks, who was seen on CCTV been thrown into a cell door at Bendigo Police Station.

Mr Meeks, who was arrested for allegedly swearing at police and acting aggressively, was left bleeding from facial injuries and suffering a bruised wrist after the alleged incident.

The allegations of brutality followed the resignation of Assistant Commissioner Brett Guerin over a series of offensive online posts made under a pseudonym.

Mr Guerin, was was the head of Victoria Police's ethical standards body, quit the force in February after being referred to the anti-corruption commission.

Using the alias 'Vernon Demerest', Mr Guerin made a series of racist comments on Youtube.

The arrest (pictured) of a Sudanese-born Melbourne man who allegedly robbed and trashed a chemist in 2016 was reported to the IBAC

'The jigaboo runs riot and out of control. The 'boo needs the lash,' read one of the vile comments.

'Wonderful to see greasy, diving, cheating dagoes get their just reward. Bitter, lingering defeat,' said another posted on a soccer video.

The comments were exposed a week after he publicly apologised last week for making graphic references to former police commissioner Christine Nixon.

In March the IBAC delivered a damning report accusing the force of failing to investigate dangerous incidents.

The IBAC itself has been criticised for its handling of complaints about Victoria Police.

An incident involving six officers allegedly beating the mental health patient with batons, verbally abusing and pepper spraying him was caught on camera (pictured)

Footage showed a man being (pictured) being punched 11 times and hit with a baton before one of the officers stomped on his back in a two-and-a-half minute ordeal

Lawyers told a parliamentary inquiry in February they do not recommend complaining to IBAC, as more than 90 per cent end up handed back to police to investigate.

Victoria Police is now in discussions with IBAC about the roadside breath test revelations, which occurred over five years.

'The investigation, which analysed over five years of data, 1500 preliminary breath test devices and more than 17.7 million tests, disappointingly found 258,463 PBTs or 1.5 per cent of all tests had been falsified,' Assistant Commissioner Russell Barrett said on Wednesday.

'I had not heard of our members engaging in such a practice, we let ourselves down, we've let the community down. It stops now.'

'There could be a number of reasons but the main rationale I believe is to hide or highlight productivity. Whatever reason our workforce may come up with, it isn't acceptable.'