Victoria Police are again under fire for using excessive force on vulnerable people, after allegedly attacking a Melton father, who they were called to do a welfare check on.

Shocking CCTV obtained by A Current Affair shows four officers talking to Mecal Hansen, who appeared to be calm, before hosing him with capsicum spray in the eyes from a close range.

“I didn’t do anything to deserve that. Like, they’re there for my safety. That wasn’t for my safety,” he told A Current Affair .

The 31-year-old claims to suffer from depression and his wife, Jessica, had called their local police station on Sunday night over concerns he was going to self-harm. But she never imagined things to go as far as it did.

“I felt pretty bad for calling the police on him, but needed to be done," she said.

“Very disappointing because that's not what they were called here for."

Mecal Hansen being capsicum sprayed by police. (Nine)

When the officers arrived, one of them was carrying a large canister of capsicum spray. Mr Hansen said the officer told him they wouldn’t use the spray on him.

“I just said as a joke 'are you going to mace me?’, and he said, 'no I just carry it around because it's easier'”.

Mr Hansen claimed he wasn’t aggressive and didn’t even raise a hand but admitted he made a wise crack to police before being pounced on by all four officers.

“Didn’t move, didn’t flinch, didn’t do anything.

“(They) tried to bend me in ways you don't bend and handcuff me… More than excessive. Completely unnecessary,’ he said.

Mr Hansen said it was one of one most painful experiences he’s ever had.

“Excruciating… It was the worst pain, I didn’t want to open my eyes.”

This event is the latest in a long line of incidents where Victoria Police have been accused of using unnecessary force on vulnerable people.

Last month, Wonthaggi father Matt Purton was pinned down by police after having a seizure and suffered a coma as a result.

And just last weekend, an off-duty officer allegedly bashed a woman at Lamby’s Tavern in Geelong.

Lawyer Jeremy King said the officers’ behaviour towards Mr Hansen was inappropriate in a situation for someone who's distressed.

“The use of OC spray in that situation is entirely inappropriate and not in accordance with police procedure. You cannot use OC spray to punish someone ‘cause they've made a comment that you don't like,” he said.

In a statement, Victoria Police said they are investigating the matter, and any officers revealed to have displayed “unacceptable or disproportionate use of force… will be held to account”.

But many have defended frontline officers. Simon Breheny from the Institute of Public Affairs said the focus should instead be on those in command.

Mecal Hansen (Nine)

“A lot of those on the frontline are doing the right thing, I think it's a question as to the whether the leadership at Victoria Police is doing the right thing.”

Mental health expert Professor Patrick McGorry said the focus shouldn’t be on police, but on the mental health system.

“I wouldn't be blaming the police here - they're placed in situations they're not really trained or equipped for - because the mental health system has really collapsed,” he said.

Despite the ordeal, Mr Hansen believes the majority of police are doing a good job.

“The two officers that stayed with me in the hospital, I can't praise them enough. The way they treated me, the way they spoke to me - that is how you treat someone when you're there to do a welfare check.”

Victoria Police issued this statement:

Victoria Police is aware of this incident and has initiated an investigation to determine all of the circumstances and gather all available evidence. As the matter is now under investigation it would be inappropriate to comment on the specifics of this case.

Victoria Police will not tolerate any unacceptable or disproportionate use of force and should this or any investigation reveal those behaviours, the police involved will be held to account.

Managing people with mental health and drug issues is complex and challenging for police, but we are committed to ensuring our officers have the awareness and training they need to confidently and sensitively interact with people experiencing mental health issues, and connect them with the support they need, when they need it.

Victoria Police is investing significantly in the way we manage mental health issues in the community.

Dedicated mental health training has been compulsory for all police recruits since 2011.

From July 2018, a baseline training package on effective communication and de-escalation tactics has been included in the bi-annual training that all police, protective service officers and police custody officers are required to complete.

This training includes strategies regarding effective communication with people experiencing a mental health issue.