University of Pretoria students were expelled from the official Tuks residence.

Pretoria - The University of Pretoria (UP) has launched an investigation into possibly racist behaviour after two white female students were photographed in domestic worker outfits with brown paint smeared on their faces and arms.

“The investigation began yesterday (Tuesday),” UP spokeswoman Nicolize Mulder said on Wednesday.

Disciplinary steps had already been taken, she said without elaborating.

The SA Human Rights Commission said it was not investigating the case as it did not receive a complaint.

“We didn't receive a complaint in this matter, we just learnt about it in the media,” said spokesman Isaac Mangena.

The picture, which had reportedly gone viral on social networking sites, was published in Beeld and The Times on Wednesday.

According to Beeld, the picture was taken at a private 21st birthday party and shows the two posing with padded bottoms.