Facebook video appears to show WA policeman punching woman in Kununurra

WA Police are reviewing a video on social media that appears to show a West Australian police officer punching an Indigenous woman who is pinned to the ground.

Isaiah Barney, who filmed the incident in Kununurra earlier this month, said a woman was being restrained by two policemen when one officer struck her in the head in front of a stunned group of onlookers.

"One officer was on her legs and the other officer was on her back and shoulders so hard," he said.

The video appears to show a police officer punching a woman who is pinned to the ground.

"I was looking at her - it was hard for her to breathe - and then I started recording.

"I was absolutely shocked, I had to literally re-watch the video to see him hit her, but I had it on camera."

Mr Barney said police had broken up a confrontation between his sister and another woman in the Kimberley town in the early hours of December 5.

"I immediately thought they had my sister and so I ran towards them and found they had the other woman on the ground," he said.

"I made it very clear to the police officer in that video that I was recording him, I screamed it out to him ... he struck the lady two times in the head."

In the video, Mr Barney can be heard telling the police officer, "I got you mate, I can see what you're doing, I've got you mate, I've got you on camera".

A woman can also be heard screaming "don't f---ing do that," after the police officer struck the woman. 

Mr Barney claimed the woman, believed to be from Fitzroy Crossing, was too intoxicated to stand on her own when the incident occurred. 

A police spokesman said the incident would be reviewed. 

"It is difficult to make comment based solely on the low quality and limited scope of the vision provided," he said. 

"While no official complaint has been made about the incident, WA Police will conduct a review."

- with AAP