Transnet says it has suspended a number of employees at the Ngqura Container Terminal near Port Elizabeth for participating in an illegal strike which is now in its second week.
According to the company, the strike at the port has had a negative impact on operations. It said the citrus and automotive industry, which relies on the port for the transportation of goods, was affected.
Workers at the Ngqura Container Terminal have been on a protracted "go-slow" over payment of incentives.
The strike has also affected operations at the Durban Container Terminal, due to high-level absenteeism, Transnet said in a statement on Thursday evening. It said that plans were in place to prioritise urgent cargo.
The state-owned firm said the impact of the strike on the economy has not yet been quantified.
In May, Transnet National Ports Authority obtained a court interdict halting a strike at its ports by South African Transport and Allied Workers Union (Satawu).
Spokesperson Zanele Sabela said Satawu members were not part of the strike at Ngqura.
On Friday morning Natasha Mazzone, DA spokesperson for public enterprises, said the DA would write to Transnet to request an urgent update on developments, adding the go-slow would have "devastating effects".