The Democratic Municipal and Allied Workers Union (Demawusa) and Metrobus are expected to meet with the CCMA on Wednesday, as the bus strike in Johannesburg enters its ninth day, the union's Dion Makhura said.
The CCMA will intervene in the negotiations between the two parties, which have deadlocked.
Makhura said the bus service's management had refused to meet some of its demands, which include salary adjustments for all new employees and salary progressions for those who have worked for the company for three to nine years.
The union is also demanding that Metrobus management looks into internal company issues, like investigating individuals for "corruptly paying allowances to bus drivers". It also wants issues of favouritism to be investigated, claiming a manager had been suspending employees without following disciplinary processes.
"We have approached the CCMA to intervene and will be meeting with them along with Metrobus tomorrow at 12:00," Makhura said.
"We said to them that we can agree [on] a process for the investigations we are calling for, because those are issues they need to investigate, but they refuse," he added.
Metrobus spokesperson Goodwill Shivuri, however, maintained that the union's concerns were already being dealt with.
"There is already a process on the investigations they are demanding, and a legal firm will be investigating. If that's the reason they are on strike, then it is immaterial.
"The issue here is salary adjustments and progressions, because there are already agreements around them," Shivuri said.
"Tomorrow, the CCMA will intervene and we will be there," he added.
Shivuri said there had been no violence this week because buses were not operating.
Johannesburg commuters on some of Metrobus's routes were left stranded on Tuesday last week after Demawusa members embarked on a strike. The bus company then suspended services, due to intimidation concerns.