The Nelson Mandela Foundation (NMF) has filed an application to appeal the ruling by the Equality Court in favour of AfriForum's Ernst Roets and his display of the old South African flag.
The leave to appeal includes an application for direct access to the Constitutional Court, NMF spokesperson Luzuko Koti said in a statement on Tuesday.
"Gratuitous displays of the old flag express a desire for black people to be relegated to labour reserves, a pining for the killing, the torture, the abductions, a melancholia for the discrimination, the death squads, the curfews and the horrific atrocities committed under the flag."
He added: "The right to freedom of expression is widely protected in our law. However, it does not protect the right to hate speech and does not trump the right to human dignity. That is so because of our history - which is a painful one."
Earlier, the Equality Court, sitting in the Gauteng High Court in Johannesburg, ruled that while Roets might in due course be held to have breached the provisions of the Equality Court Act, he was not in contempt of court, News24 reported.
READ MORE: Apartheid flag: AfriForum's Ernst Roets not in contempt of court, judge rules
While handing down judgment, Judge Colin Lamont said: "This, in my view, is precisely why the order does not contain a directive prohibiting the display of the flag. There is no order "
However, the NMF, in its application, argued that the court "fail[ed] to consider that contempt of court consists in 'the commission of any act or statement that displays disrespect for the authority of the court' ... or in 'violating the dignity, repute or authority of the court'."
It further argued the court did not consider that contempt of court could apply to someone who "has been setting the court at defiance, and deliberately treating the order of the court as unworthy of notice".
"The court failed to interpret and apply common law in line with the Constitution especially section 1(c) and section 165 to afford an appropriate degree of protection to the 'dignity, accessibility and effectiveness of the courts'."
Lastly, the NMF said it had presented proof that Roets was in contempt of court.
"The court should have found that the applicant had presented proof that the respondents had committed contempt of court, sufficient to find that they had a case to answer, and should consequently have issued a rule nisi to enable that case to be answered appropriately."
Last month, Roets tweeted a picture of the apartheid flag hours after the same court had declared the gratuitous display of the flag was hate speech.
His tweet caused outrage on the social media platform, and prompted the NMF to take him to court for contempt of court, News24 reported.