Cosas has warned teachers aligned to Sadtu in Ekurhuleni they will be barred from returning to school if they embark on an intended march in the area.
"We call upon all students in all corners of Gauteng to guard and monitor that ... any teacher [who] leaves our schools [for the planned march] ... doesn't come back to our premises because they have shown themselves [to be] self-centred and not caring about the future of the black child," read a media statement signed off by Congress of South African Students (Cosas) Gauteng chairperson, Collen Malatji, on Thursday.
Cosas said it was aware that Sadtu teachers were planning school "disruptions" in Ekurhuleni next week. Malatji told the Mail & Guardian the planned march was organised over a principal facing charges by the Gauteng education department.
"It's a march of no reason, a march to protect someone who's understood to have been charged [for wrongdoing]," said Malatji. "There are processes to be followed when someone has been charged. The union cannot be used for such things."
Cosas structures in Gauteng decided in an "emergency meeting" this week that learners should act against teachers taking part in the march, Malatji said.
The march that Ekurhuleni teachers have planned "undermines our main objective of making sure that the interests of students are championed", Cosas said its statement. "We call upon responsible teachers not to respond to a reactionary call of disrupting our lessons on the eve of the matric preliminary examinations and final exams."
The education of marching teachers' students would not be disrupted "because their interests are guarded in private schools," Cosas added.
Cosas appealed to the education department to "respond harshly to teachers who don't take the responsibility of teaching seriously".
A department spokesperson confirmed a teacher in Ekurhuleni faced charges but said he would not comment any further because the "matter [was] sub judice and [was] on appeal".
Sadtu's provincial secretariat is not aware of the planned march, provincial chairperson Eddie Kekana told the M&G. "We're not aware of any march being planned by any of our [regional] structures. We'll check with Cosas where is that particular march planned."
But the M&G understands Sadtu members in Ekurhuleni decided in favour of a march this week.
The union's provincial leadership is aware of the decision but it is understood it does not support it.
Sadtu has in the past been criticised for putting its members' interest ahead of pupils' education. "We're tired of Sadtu holding us to ransom," said Malatji.