Motorists were advised to avoid the M1 highway, after a 26-wheeler paint truck overturned on Monday morning leaving 400 metres of the highway to be covered in white paint.

The road was closed in both directions from the Empire Road off ramp to the Smith Street offramp, said Superintendent Wayne Minnaar of the Johannesburg metro police.

"We have opened one lane to contra flow traffic, while clean up operations take place."

Sand blasting machines with water were being used to clean the road.

"They are probably not going to be done by the afternoon as there is still a lot of work to be done."

Motorists were advised to use the N1 or the N3 highways.

The accident occurred on the M1 north on Monday morning, when a 26-year-old driver lost control of the truck causing it to overturn.

Netcare 911 spokesperson Nick Dollman said the driver's left leg had been "traumatically amputated" above the knee when the truck overturned.

Paramedics and fire fighters used the Jaws of Life to pry a small opening between the roof of the truck and the road surface, in order to get the man out.

He was taken to a trauma unit at Milpark Hospital where he was placed onto life support machinery shortly after arrival, and is still in a serious condition.