Twenty-five years on from the collapse of apartheid, one of South Africa's most popular TV soap operas has shed stark light on the country's ongoing battle with racism after showing its first on-screen inter-racial kiss.

The long-running SABC2 show 7de Laan was compelled to condemn "hate speech" after reports of threats to actors Carina Nel and Nicholas Nkuna, who played the moment of intimacy.

"As much as we respect our viewers’ right to voice their opinion, 7de Laan will not tolerate hate speech, racism or instigation of such narratives by any member of the public or media," its makers said in a statement pinned on the programme's Twitter account.

Ugly social media exchanges followed the Afrikaans soap's January 15 episode, with one Facebook post reading: "I don’t want to teach my kids these thing. Drugs, alcohol abuse, hostages, suicidal thoughts, and now, the cherry on the cake, mixing race. I am not racist, but white with white and black with black."

While the scene has exposed the lingering problem of racism, many have celebrated the breaking of a long-time taboo on South African television.

"I am jumping," one delighted viewer posted. "Make them aware that interracial relationships is perfectly fine."

Another wrote: "Well done for showcasing and addressing the interracial relationships, ... please dear people - it's a soapie, if you hate the skin colour of another person, then you hate one of your own."