Batteries and diesel were stolen from two trucks during a protest on the R103 between Ladysmith and Colenso in KwaZulu-Natal on Monday.
Early on Monday morning about 200 protesters blockaded the road with burning tyres.
"They stopped and offloaded then set alight the crates that were on two trucks. The batteries and the diesel were also stolen," said KwaZulu-Natal police spokesperson Col Thembeka Mbele.
"The police are at the scene to stabilise and monitor the situation. A case of public violence is being investigated by Colenso police," Mbele said.
Alfred Duma local municipality spokesperson Siyabonga Maphalala told TimesLIVE that a municipal delegation would visit the community on Monday.