President Jacob Zuma's children were all in a stable condition and were being treated for various injuries, spokesman Mac Maharaj said in a statement.
The children were at a hospital in the city of Pietermaritzburg, in the eastern KwaZulu Natal province, he said.
The accident happened this morning, Maharaj said. "The Presidency wishes the family all the best during this period and wishes the children a speedy recovery," he said. No further details were given.