Protesters in Zamdela, Sasolburg, tried to burn down the local police station on Tuesday, Free State police said.
"Rubber bullets were fired and water cannons were used to disperse the protesters," spokesperson Constable Lebohang Mareletsa said.
Police vehicles were damaged and windows at the police station smashed.
A group of youths set a spaza shop alight, but residents extinguished the fire. By noon, most protesters had dispersed, while others stood in groups, watching the streets.
Some were overheard saying they would regroup after having lunch.
The violence, which started on Sunday, was sparked by plans to merge Sasolburg with the Ngwathe local municipality, under which Parys falls.