CCTV obtained by the ABC shows two Victoria Police Protective Services Officers allegedly assaulting a man at a Melbourne train station after he refused to let them search his bag without a reason.

Moustafa Sayegh said he was approached by two PSOs at Jacana Station at Glenroy, in Melbourne's north-west, last June.

He said they asked him where he was going and requested to search his bag, but he declined when they did not provide a reason.

What are your rights? PSOs can ask you for your name and address if they suspect you have committed, or may be about to commit an offence

PSOs can ask you for your name and address if they suspect you have committed, or may be about to commit an offence PSOs cannot ask for your date of birth

PSOs cannot ask for your date of birth Police say you can record your interaction with PSOs on your phone

"They have no right to... why go through the embarrassment of having people walking past and see you being treated like a criminal?" he told the ABC.

Mr Sayegh said the officers then became aggressive and one lunged at him when he tried to record the encounter on his phone.

The vision shows the officer leap towards him, then a scuffle, as both officers hold him against a railing.

"The PSO on my left was punching me in the ribs and elbowing me to the side of the head," he said.

"I was quite terrified, because they'd become so aggressive and out of control."

Victoria Police declined to be interviewed about Mr Sayegh's allegations, but in a statement said Mr Sayegh had not lodged a complaint.

ABC News also obtained a recording of the officers calling for back up, in which Mr Sayegh can be heard calling for help.

"I'm being assaulted, I'm being assaulted by two police," he shouts in the recording.

"I had pain in my ribs, I had pain in the side of my head at that point I was thinking there's only one thing further for them to do and that's for them to start using their weapons against me," Mr Sayegh told the ABC.

One officer can then be heard saying, "he's still resisting (arrest), get the handcuffs here".

Mr Sayegh said when one of the officers dislocated his thumb he lashed out and kicked the officer.

He has been charged with assaulting a PSO.

A PSO attack could prove fatal: community legal centres

The Federation of Community Legal Centres released a report on Tuesday warning it was concerned an altercation with PSOs could turn fatal.

The report found PSOs, who are armed with guns, were using excessive force and questioning people in a way they were not authorised to.

"Our number one concern is the number of times that PSOs are asking, or rather, demanding information from people," the federation's Michelle McDonnell said.

"When people are innocently sitting and waiting for their train, they're being asked questions they don't feel comfortable answering.

"We're finding these kinds of exchanges can actually develop into conflict situations."

Ms McDonnell said she also had concerns about the excessive use of force by PSOs.

"We've had situations where people have been physically handled and bruised, we've had people who have been forced to the ground and handcuffed so that PSOs could go through their bags," she said.

Officers 'provide little value at extreme expense'

RMIT's Professor Peter Norden has also raised issues with PSOs and said they question people because they had little else to do.

"Train stations in Melbourne have never been places of high crime activity," Professor Norden said.

"We have less trained officers with little to do standing in the cold through Melbourne winters with guns and capsicum spray.

"If I was standing on a quiet platform with nothing to do, I'd be looking to get involved."

Mr Sayegh said he thought that was the reason he was targeted.

"They were obviously bored at the time, and wanted someone to have a conflict with," he said.

Professor Norden called for the Victorian Government to review its policy.

"The practice of armed guards on every railway station in Melbourne was part of a desperate measure of a previous government to obtain power, it's of extreme expense and dubious value," he said.

"I think it's now time for the Victorian Government to review this practice."

But Victoria Police defended its PSOs and said they performed a vital role in the community.

"If we do find situations where they use force inappropriately, we'll take action to address that," Acting Deputy Commissioner Jack Blayney said.

"But we've got nothing in front of us that suggests this is a widespread practice.

"(PSOs) perform a vital role within the community... on a day to day basis, they're spat on, they're insulted.

"It's a very challenging environment for them and they do a great job in that."