"It entrenches white supremacy that we fought against during the liberation struggle," said Zet Luzipo, provincial secretary of the Congress of SA Trade Unions.

He said the poster, crafted by the Democratic Alliance Students' Organisation, opened up old wounds and it was not about education.

"The posture says join the DA to have an affair with a white person. The DA thinks our struggle for democracy was about the Immorality Act and the Group Areas Act," Luzipo said.

"We will not be excited with having an affair with a white person; we will not be enticed by that."

He said if the DA wanted to discuss non-racialism this would be welcomed.

"We must address inequality between black and white learners. We must discuss how far we have come since 1994."

DA youth leader Makashule Gana said the poster was part of a campaign to create debate about race.

"To say that the poster is sexual is taking it to the extreme. The poster is saying a lot," Gana said.

"They are embracing each other, and it shows in this country that we can find an opportunity to embrace each other."