Johannesburg - Violence undermines the genuine demands of striking workers, Labour Minister Mildred Oliphant said on Wednesday.
"There is no reason whatsoever for industrial action to be accompanied by violence... Our laws guarantee the right to protest," she said in a statement.
She condemned recent reports of violence in New Germany, KwaZulu-Natal, where a petrol attendant was seriously injured in an altercation, believed to be strike-related.
Oliphant called for negotiations to resume under the auspices of the Commission for Conciliation, Mediation and Arbitration (CCMA).
The National Union of Metalworkers of SA (Numsa) said on Tuesday that negotiations with employers had yielded no results.
"I have requested the CCMA to assist parties in finding a peaceful resolution to their labour dispute and I expect them to engage and cooperate with the CCMA," Oliphant said.
Numsa national coordinator in the motor industry Elias Kubeka said he was aware of the minister's call for intervention.
"The CCMA intervention will be discussed later today [Wednesday] within Numsa," he said.
Plans for talks to resume with the Fuel Retailers' Association (FRA) and Retail Motor Industry (RMI) were under way.
"We would like to resume the negotiations with the FRA and RMI tomorrow [Thursday], though issues of [parties'] availability still need to be finalised," Kubeka said.
The union has demanded a R30 an hour across-the-board increase by 2016 on actual rates of pay in all sectors, and divisions for workers earning above R6 000 a month. It has rejected a revised wage offer of 7.5%, sticking with its demand of a double-digit percentage increase.
Petrol attendants and car repair workers affiliated to Numsa began the nationwide strike 10 days ago.