Cosatu's North West branch on Monday called on a rival labour union to put an end to the violence at Lonmin's mine in Marikana.
Provincial secretary Solly Phetoe said the Association of Mineworkers and Construction Union (Amcu) should give miners freedom to choose a union.
“Cosatu wants to remind Amcu that the Constitution of our country allows workers a freedom of association,” Phetoe said.
“That right has been extended in the Labour Relations Act which give workers the rights and powers to form their unions, and not to be forced to join some fly-by night unions.”
Violence at the mine had been linked to clashes between members of the Cosatu-affiliated National Union of Mineworkers and Amcu, which were reportedly fighting for control of local mines.
Four people had been killed in violence at the mine in the past four days. A man was found gunned down on the mine's premises on Monday. Another died in hospital after being attacked with a panga on Sunday.
Two security guards died on Saturday when their car was set alight. Four other workers were shot and wounded on Friday and Saturday. Eight vehicles were torched on the mine property on Sunday.
Police spokesman Brigadier Thulani Ngubane said on Monday that no arrests had been made.
“We are investigating a case of murder, arson, and malicious damage to property.”
The province's Congress of SA Trade Unions urged the authorities to arrest the killers.
In February, the two unions clashed over membership at Impala Platinum's mines in Rustenburg. - Sapa