The rap-rave duo Die Antwoord has been visited by social workers to establish the safety of their 17-year-old biological child in Cape Town.

The Western Cape social development department obtained a court order from the Cape Town Children's Court on Tuesday, giving them access to inspect the safety of the child after allegations of child abuse and neglect against Waddy Jones (Ninja) and Anri du Toit (Yolandi Visser) were published by News24.

The duo has one biological child, who lives with them in Cape Town, and three foster or adopted children, who are back with their families or caretakers in Johannesburg.

According to News24's sources, the couple has been living at the upmarket Dorp Hotel in Schotsche Kloof, Cape Town, since their 20-year old foster son, Gabriel "Tokkie" du Preez, in April accused them of treating him like their child slave.

Du Preez accused Jones and Du Toit of exposing him to pornography and nudity as a minor, abusing his child labour for their music videos and of encouraging him to participate in violent activities.

Du Preez, his minor sister and another minor boy from Johannesburg have all been living with Die Antwoord in Cape Town for various stints, but are currently back in Johannesburg. Various sources have told News24 they were treated differently to the couple's biological daughter in terms of quality of education and general upbringing.

The police are investigating a criminal case - and Captain Veronica Banks, of the Gauteng serial and electronic crimes investigation unit, has been appointed to lead the probe.