People are being urged to record their interactions with police on their mobile phones in a Black Lives Matter-style campaign to hold police to account.

At a "Copwatch" workshop in Perth this week, human rights lawyer George Newhouse showed a predominantly Indigenous audience of adults and teenagers how to safely and legally record interactions with police to be used as evidence in court.

The centrepiece of the workshop was phone vision taken by two children which appears to show a man being knocked down by a police car in the Perth suburb of Thornlie in May.

Both Indigenous and non-Indigenous people joined a workshop to learn about the program Copwatch. ( ABC News: Sarah Collard )

Inspired by the Black Lives Matter civil rights movement, the Copwatch program, which is being rolled out nationally, was set up in the aftermath of the riots sparked by the death of 14-year-old Elijah Doughty in Kalgoorlie.

Professor Newhouse said many Indigenous elders in the Kalgoorlie community wanted their people to get empowered, not angry.

Shaun Harris (left) whose niece, Ms Dhu, died in police custody, spoke at the workshop run by George Newhouse. ( ABC News: Sarah Collard )

"What we're teaching at Copwatch is empowerment through technology and the internet," he said.

Copwatch encourages citizen journalists to consult a lawyer or elder before posting vision to social media.

The first footage of the Thornlie incident — shot by a primary school-aged girl who lived nearby — was posted on Facebook by Noongar man Mervyn Eades, who brought the Copwatch program to Perth.

It was blurry and taken from a car some distance away.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 30 seconds 30 s Man struck by police car

In response, Police Minister Michelle Roberts said police officers would be interviewed about the incident.

The second piece of vision, taken by a teenage boy from a car in a different location, was posted by Mr Eades two days later.

It provided a clearer but disturbing view of the man convulsing and being handcuffed.

The man filmed by the children in Thornlie suffered bruising in the incident. ( Supplied: Mervyn Eades )

Soon after it was posted, a senior sergeant was stood down.

An internal police investigation is ongoing.

Mr Eades said many people were unaware of their rights.

"If you're in a public place and police are performing their duty in a public place, you are perfectly entitled to film them and you don't have to stop," he said.

Mervyn Eades, the chief executive of Ngalla Maya, says officers should be held accountable for their actions. ( ABC News: Sarah Collard )

But he said it was important that people filming officers did not interfere with police operations.

"A big message to our community is stay at a safe distance. Don't go putting your cameras in police's face, antagonising them," he said.

A WA Police spokesman also urged members of the public to be "mindful of their personal safety while filming" and not interfere with police operational activity.

CCC finds filming police 'not obstructive'

An incident recently investigated by WA's corruption watchdog showed that some police officers do not understand the rules around filming.

Earlier this year a WA police officer was stood aside just hours after the release of disturbing footage of him unlawfully tasering a man who had been stopped for a random breath test.

The video was filmed by one of the passengers in the car driven by taser victim Bill Holt (not his real name) who was told by another officer at the incident that he was not allowed to film.

But in its investigation, the Corruption and Crime Commission said the officer, identified as Senior Constable Arnold, was unjustified in charging the passenger with obstruction.

"Filming police using a mobile device at a reasonable distance is not obstructive and cannot constitute an offence," the CCC report said.

Police union supports body cameras

Police in many states, such as New South Wales and Queensland, wear body cameras, though the rules that apply to them differ.

In WA, only motorcycle traffic police are equipped with them.

WA Police Commissioner Chris Dawson has called for all frontline officers to wear cameras. ( ABC News: Lindsay Brennan )

This could change if the WA Government agrees to fund new WA Police Commissioner Chris Dawson's call for all frontline officers to wear cameras.

Commissioner Dawson recently told a parliamentary committee the cameras would improve accountability and protect all parties in an incident.

"We know that it is almost common practice now: whenever police stop and speak to someone, bystanders will video it," he said.

"So the anomalous issue I have as commissioner is that I am not getting that video myself … so we are on the backfoot already."

He is supported by the WA Police Union, which argues the cameras would boost the safety of officers and provide crucial evidence.

"Video evidence would give magistrates an accurate, warts-and-all portrayal of the alleged offender," union president George Tilbury said.

Justine Damond Ruszczyk was shot dead by police officer Mohamed Noor outside her Minneapolis home last year. ( Linkedin: Justine Ruszczyk )

But it is unclear exactly how the cameras could be used — for example, when they can be turned on and how the vision is accessed.

As the example of Australian woman Justine Damond Ruszczyk shows, the trust between police and the public can erode if one side is perceived to be misusing the cameras.

The 40-year-old was shot dead by police officer Mohamed Noor outside her Minneapolis home last year after she had called to report a suspected crime.

Her father is suing Mr Noor and his partner Matthew Harrity, among others, accusing the officers of trying to conceal the facts around the shooting by not turning on their body cameras.