A group of police officers will be investigated after being caught on camera pinning down, beating and dousing a Melbourne disability pensioner with capsicum spray and a garden hose.
Victoria's anti-corruption commission will now investigate the incident outside the pensioner's Preston home in September which was caught on CCTV.
Assistant Commissioner Luke Cornelius said he was "very concerned" by the security footage obtained by The Age and shared with the ABC.
"The members involved clearly needed to be called to account for their conduct," he told reporters on Tuesday.
But Mr Cornelius added it was not police practice to stand down officers when a complaint was made.
Any such decision would follow the outcome of any Independent Broad-based Anti-corruption Commission's investigation.
Robinson Gill Lawyers accuse six officers of mistreating their client, named only as John, after arriving at his Preston home to conduct a welfare check.
John's CCTV system showed him trying to fend off the officers before being capsicum sprayed and dragged onto his lawn, where he was sprayed again.
"F***ing idiot, do you like that? Do you like that? Smells good, doesn't it?" an officer is heard saying.
The footage also showed an officer hitting John's leg with a baton.
During the ordeal, John is wailing "Oh my back, my back".
While being sprayed with a garden hose, John added: "You happy? ... how tough are youse (sic)?"
Lawyer Jeremy King said the footage was "very confronting and very distressing".
"John's case is a particularly egregious example but unfortunately police misconduct is widespread," Mr King told AAP.
Mr Cornelius admitted police had work to do to win back the public's trust over how complaints were handled.
"John, if you're listening to this, I want you to know I was concerned by what the CCTV footage depicted," he said.
"Our officers make mistakes like anyone else, and when that happens we seek to learn from them.
"And when those mistakes are not mere mistakes but as a result of intentional conduct then, of course, we seek to hold those officers to account."
Premier Daniel Andrews said he had not watched the footage but defended the force.
"Victoria Police, as the nation's best police force, conduct themselves with professionalism and in my experience proportionate to the risk that they face," he said.
Opposition Leader Matthew Guy labelled John's case "abhorrent" and said it highlighted the need for a better police complaints system.
"All Victorians will be outraged by it," he said.
An IBAC report last week found Victoria Police failed to adequately manage conflicts of interests, consider human rights and examine relevant evidence in serious incidents when people were hurt or killed.
Mr King previously told a parliamentary inquiry into police oversight an independent body was needed to investigate allegations of misconduct.
While Victoria Police continue to reject calls for such a body, Mr Cornelius on Tuesday said the public needed to be assured "mates are not investigating mates".