A Barberton, Mpumalanga, father faces a charge of statutory rape after making his own 17-year-old daughter pregnant.
The girl has already given birth to a child after a relationship that has allegedly been going on for almost six years.
Police said this was the second time that the victim had carried her father's child.
In the first instance the father had allegedly forced the girl to terminate the pregnancy.
The abuse was revealed on Monday when the girl told her priest that her father was responsible for the child.
Shocked by the disclosure, the priest informed the police. The police said the 42-year-old suspect started sleeping with his daughter in 2002 when she was only 11 years old.
"The case surfaced when a priest told us the girl had identified her father as the person responsible," police spokesman Constable Jabu Ndubane, pictured, said.
The girl gave birth to a baby girl in March.
"The suspect has been living with the victim and her 12-year-old brother since 1999 when he separated from their mother," Ndubane said.
The girl's mother lived in Tonga, about 100km from Barberton.
The suspect is expected to appear in the Barberton magistrate's court today on a charge of statutory rape.