Protesters blocked roads in Boksburg, east of Johannesburg, on Monday morning, police said.

Rondebult road between Main road and Leeupoort road was impassable, police spokesman Kobeli Mokheseng said.

"The intersection is blocked off with burning tyres, rubble, rocks and foreign objects," Mokheseng said.

The roads had been blocked since the early hours of Monday.

Police were not yet sure who was responsible for the protest or the reason for it.

"We will investigate and trace the people responsible for the protest," he said.

No arrests had been made and no injuries were reported.