The National Union of Metalworkers of South Africa said on Tuesday it had lodged a dispute at the Commission for Conciliation, Mediation and Arbitration (CCMA) against ArcelorMittal South Africa (AMSA) after reaching a deadlock in wage talks.
The union is demanding an 11% wage increase across the board, a rise in the company's medical aid contribution from 60% to 80%, and a one% increase in the provident fund contribution, among others.
AMSA has offered a 7.5% pay hike for the lowest paid worker, 6.5% for the highest paid, 6.3% for directors, 6% for management and a 6.5% increase in the company contribution to medical aid.
"We reject this offer because our members feel the offer made by the employer will not make an impact on their lives," Numsa said.
"Our members are struggling under the burden of the VAT (value added tax) increase, as well as the negative impact of the fuel hikes. The offer made by the company does not go far enough in addressing these immediate and pressing concerns for workers and their families."
It warned it would embark on a strike if the company failed to address these "fundamental demands".
The CCMA hearing is scheduled for Wednesday.