Footage from the incident at the woman's Brisbane home was posted on Facebook by NITV journalist Danny Teece-Johnson and has already amassed more than 629,000 views and 11,000 shares.
The officer pushes the woman backwards four times with increasing force as she demands to know why her teenage son is being arrested.
The final time he grabs her neck and pushes her to the ground.
Police are reviewing footage of Saturday night's incident, but Queensland Police Union president Ian Leavers has rushed to the officer's defence.
"I believe the police showed a lot of restraint and the only thing I would of done differently - I would have arrested her well before they did. But it's a judgment call and they had to do what they did at the time," he told ABC Radio on Tuesday.
"How many times does somebody have to be told to move back and let police deal with the arrest?"
Mr Leavers said the woman should have let the arrest proceed and then either asked the officers about it or taken the matter to court.
"But don't become involved and make a violent situation more dangerous," he added.
The woman said seeing her son screaming and in pain had caused her to automatically act in the way any mother would have.
"I just couldn't believe that he was basically hitting me when they are against domestic violence with women or anybody," she told NITV.
"It was a bit terrifying to see my son being hurt by them when I thought they were here to protect."
Share
