The ANC is expected to lay criminal charges against Afrikaans singer Steve Hofmeyr, accusing him of issuing death threats on social media.
"His racist and inhumane rants on social media which smacks of barbarism, white supremacy and toxic masculinity," the ANC said in a statement on Sunday.
The charges come after threats he made to South Africa's ambassador to Denmark, Zindzi Mandela, and DA MP, Phumzile van Damme, on Twitter.
The controversial singer tweeted to both women, saying: "Dear @zilevandamme and @ZindziMandela I'm a South African tax-paying citizen. Effectively, I AM your boss. You WILL jump when I say so and you WILL ask how high. And when you come to take our lives&land, you WILL die. Our contract is that simple. And don't you forget it."
The ANC urged South Africans to isolate people "that continue to promote racism in our country". The party said it remains resolute in its campaign of building a "non-racial, democratic and prosperous society".
The party said it would lay charges of crimen injuria against Hofmeyr at the Johannesburg Police Station at 13:00.
Van Damme made headlines on Tuesday after she punched a man at the V&A Waterfront after he came into her space and allegedly said, "voetsek you black", before throwing her phone on the ground.
Mandela wrote a series of tweets from her account aimed at "apartheid apologists" and "land thieves".