Talks between Transnet and unions Untu and Satawu are continuing at the CCMA on Tuesday.
Workers at the state-owned freight utility have been striking since last week.
Untu members downed tools on Thursday and their counterparts from Satawu joined them on Monday.
They want wage increases of between 12% and 13.5%.
Last week, Transnet offered them between 3% and 4% but they rejected this.