Education Minister Naledi Pandor has warned teachers against electioneering during school hours.
This comes after teachers at Witkoppen, Diepsloot, Lanseria and Cosmo City, north of Johannesburg, missed school to attend a mass meeting at Cosmo City Secondary School to discuss the ANC election plan.
The meeting was organised by the South African Democratic Teachers Union (Sadtu).
Pandor warned against conducting "any campaigning directed at pupils and teachers during school time".
"Such an action impacts negatively on our resolve to improve the quality of education. Campaigning must only take place after school hours," Pandor said.
Sadtu regional secretary Ronald Nyathi said: "Meeting times are dictated by circumstances such as demographics and their importance. We always notify the department about meetings."