The 22-year-old was arrested after a 19-year-old woman opened an assault case against him, said Sergeant Marinda Stoltz.

Stoltz said: "The woman was allegedly fighting with her boyfriend during a small gathering at Mr Pistorius' house on Saturday afternoon.

"Mr Pistorius told them to go outside."

She said Pistorius' friend returned to the house alone, prompting the woman to start kicking the doors.

Stoltz said: "It was while she was kicking the doors that Pistorius allegedly opened the door and told her to leave his house. 

"When he closed the door on her, one of the door panels allegedly hit her on the leg... she sustained bruises."

The woman, who is also a resident of Silver Lakes, an up-market, residential and golfing estate in Pretoria, then went to the Boschkop police station to report an assault case.

Pistorius, nicknamed "Bladerunner, who won the 100, 200 and 400 metres at the Paralympics in Beijing last year, was charged with assault with intent to cause grievous bodily harm but the charge was changed to common assault this morning, said Stoltz.

She said Pistorius was released with a warning to appear in court.

Stoltz said: "The case is still in a sensitive stage so we can't give out more information at this stage."

Earlier this year Pistorius was investigated by authorities after a motor boat accident on the Vaal River in which he sustained facial injuries and which threatened his season.

He subsequently made a full recovery and no charges were ever brought against him.