Labour union Solidarity will lay charges with the police and the Equality Court against members of Black First Land First (BLF) on behalf of several parents of the victims of Hoërskool Driehoek disaster.
"We cannot allow a fringe figure's racial hatred to be normalised.
"The statements of the BLF have reached an extremely low point where hate speech is concerned and if we left it at that, we regard it is acceptable," Solidarity chief executive Dirk Hermann said in a statement on Wednesday.
This comes after BLF spokesperson Lindsay Maasdorp responded to a post by Facebook user Siyanda Gumede in which he said he was unmoved by the pupils' deaths as they meant the elimination of three "future problems" from the world.
Roydon Olckers, Jandré Steyn and Marli Currie died on the scene when a concrete slab above a corridor linking two blocks of buildings at Hoërskool Driehoek came crashing down earlier this month. A fourth pupil, Marnus Nagel, later succumbed to his injuries in hospital. The four were buried last week.
Fourteen pupils remain in various hospitals in the province.
Solidarity plans to lay a charge of crimen injuria with the police on behalf of some of the parents.
"The charge will focus on the violation of human dignity which includes racial hate incitement. The charge at the Equality Court will focus on hate speech," Hermann added.
The union plans to also lay an additional charge at the Electoral Commission of South Africa (IEC) and request that the BLF be banned from participating in the upcoming May election.
The South African Human Rights Commission, which said it was appalled by the utterances of the BLF spokesperson, confirmed that the commission received 80 complaints on the same day the social media comment was made.
The comments were "insensitive, offensive, and inappropriate and do not align with the ideals and aspirations of our constitutional democracy", spokesperson Gail Smith said.
Solidarity will hold a media conference on Thursday where a parent at Hoërskool Driehoek is expected to read a statement on behalf of some of the victims' parents and the community.