A Sydney mother has lodged an official complaint with police, claiming an officer physically assaulted her during a traffic stop in Northmead.

Jeanny Morris says she was handcuffed and slammed against a car bonnet in front of her crying son - for failing to obey a traffic sign.. inside a McDonald's restaurant car park.

The marks on Ms Morris's wrist and hand have almost healed.

Ten days ago, they looked like this - cut, bruised and swollen.

Injuries she says - were inflicted by a police officer.

"I was crying for help," Ms Morris told 7 News.

"I said, 'can you let go of me you're really hurting me'", Ms Morris said.

Last week, she took eight-year-old son Jude to McDonald's in Northmead, at the drive thru an officer ordered her into a waiting bay.

"He approached me on my window saying 'did you realise that you just broke the law?'", Ms Morris said.

The 44-year-old had disobeyed a 'left turn only' sign inside the car park. She told the senior constable the broken sign was twisted.

"I told him I didn't see that and I was really sorry. He just goes, 'what kind of mother are you?'", Ms Morris said.

Then she tried to collect her food.

"As soon as I got out of my car he twisted my left arm and slammed me to my car bonnet in front of my son," she said.

After refusing to hand over her license, the public servant says she was handcuffed and her face was pushed against the glass.



Ms Morris says the officer grabbed her license out of the car, took her details, then let her go.

"My baby boy was crying," she said. "He was petrified".

A week later - three fines worth almost $700 arrived in the mail - for failing to obey the sign, her son not wearing a seatbelt and refusing to show ID.

A security camera captured the same officer at Ms Morris house yesterday - telling her her license had been suspended.

She was so scared she called triple-zero and more police arrived.

"She's frightened, being a lady and being all by herself," neighbour Shiv Narayan told 7 News.

Ms Morris has now lodged an official complaint, alleging assault.

"I just could not believe, you know, like your worst nightmare", she said.

Police are now investigating.