Around 6.40pm, the 39-year-old victim was driving her black Ford Kuga on the A70 when she observed a man lying on the roadway.
She got out of the car to assist him and the man assaulted her before running off. The woman managed to call for help and she was taken to University Hospital Wishaw to be treated for bruising and cuts to her head and body.
The suspect is described as around 5’7” tall, had a local accent and was wearing a dark hooded top, skipped cap and dark face mask. He was smelling of alcohol and it is believed that he may have been in the area for some time.
DI Kirsty Moore said: “This was a despicable incident, leaving a woman injured and extremely traumatised when she had only stopped to help someone she believed to be injured or unwell.
“It is vital we trace this man and I ask anyone who was in the vicinity of Shield Burn on Sunday evening, and may have seen a man of this description, to get in touch immediately.
“I also urge anyone who was driving in the area to check their dash cam footage as they may have captured him at some point in the evening.”
Anyone with any information should contact police via 101 or alternatively call Crimestoppers on 0800 555 111 in confidence.