Solidarity is expected to announce legal action on Tuesday to have what it described as the "unlawful suspension" of Laerskool Schweizer-Reneke teacher Elana Barkhuizen lifted.
The trade union and Barkhuizen are to address a media conference in Centurion at midday about "recent events at the town's primary school", it said in a statement.
It would also "announce certain steps to be taken" against the North West's Education MEC, Sello Lehari, whose "hasty and populist actions" led to Barkhuizen's suspension, Solidarity chief executive Dr Dirk Hermann said.
"Had he listened to the other side, he would have reached a different conclusion. However, he charged and convicted her in bundu court fashion in the presence of a worked-up crowd."
Laerskool Schweizer-Reneke is embroiled in a race controversy after a viral picture - allegedly taken by Barkhuizen - showed pupils at the school seemingly separated according to race.
News24 previously reported that she ostensibly posted it on a WhatsApp group for parents and was later suspended by the provincial department. The teacher who allegedly separated the children remains at the school.
According to Solidarity, Barkhuizen will "make a brief statement" at the media conference, but will not take questions or grant interviews.
The trade union said it would also announce steps that are to be taken against political parties that "exploited the incident for political gain".