Workers at South Africa’s state-owned logistics firm Transnet will go on strike from Thursday over a wage dispute, two labour unions said, in a move that could halt the export of key minerals and other cargo.

Transnet has been operating below capacity due to a shortage of locomotives, poor maintenance and vandalism and theft of its infrastructure, costing miners billions of rand in potential revenue.

A strike would paralyse freight rail services and impact South Africa’s ports, also managed by Transmembrane .

The United National Transport Union (UNTU), the biggest labour union at the company, said it had served notice to begin industrial action on Thursday.

The other union at Transnet, South African Transport and Allied Workers Union (SATAWU), said it would join in the strike from Monday.

Both unions said Transnet’s offer of a 1.5 percent pay increase from October 1 fell below their demands.

“Transnet…must provide a salary increase offer that is aligned with the increased cost of living, to cater for housing, medical ,  and the consumer price index (CPI) that is currently running at 7.6 percent,” UNTU said in a statement.

In recent years, the cost of living has soared in Africa’s most developed economy, worsened by the COVID-19 pandemic and the increase in prices of items like bread due to global supply chain disruptions since Russia’s invasion of Ukraine.

In July, former President Thabo Mbeki warned that there could be an “Arab Spring-type uprising” in the country due to the situation.

Transnet has said any increase beyond its current wage offer would not be sustainable