DURBAN - Highveld Steel spokeswoman Cathie Lewis confirmed the strike. It was not clear how many workers were involved.

The strike was called by the National Union of Metalworkers of SA. Lewis said it was believed to be in protest against potential retrenchments.

The company informed unions on May 4 that it planned retrenchments as part of its fixed cost reduction programme.

So far there had been no retrenchments, but the company was in the process of shutting down the plant, she said.

Numsa steel sector co-ordinator Steven Nhlapho could not be reached for comment.

Deon Reynecke, who heads the Solidarity trade union's metal and engineering sector, said it was not on strike and was still negotiating with management about the retrenchments.

He said Solidarity had asked management to give assurances about the safety of its workers, after striking Numsa workers reportedly stopped a coal truck and tipped some of its load onto the road accessing the steelworks.