NPA Western Cape spokesman Eric Ntabazalila said the constable was released on a warning, on condition he stay out of the Tafelsig area and not contact the complainant.
The case was postponed until November 7 for further investigation.
The Independent Police Investigative Directorate (Ipid) said the constable, from the Grassy Park police station in Cape Town, was arrested on Tuesday.
“It is alleged that the police official and the victim [14-years-old] have been having sexual intercourse between July and August 2013 at the policeman’s house, which is in the same street as the victim’s home,” Ipid spokesman Moses Dlamini said in a statement.
The girl’s friend told her mother.
Dlamini said each of the incidents had happened when he was off duty.
Ipid is an oversight body which investigates allegations of crime against police officers.