A South African judge on Tuesday postponed until August 19th the murder trial of global athletics star Oscar Pistorius, who has been charged with shooting dead his girlfriend on Valentine's Day.

Pistorius, 26, had to make his way through a scrum of photographers and reporters as he made his first formal public appearance since his release on bail in February.

The double amputee athlete, nicknamed "Blade Runner" for the prosthetics he uses in competition, has admitted shooting Reeva Steenkamp, 29, four times through a locked bathroom door on February 14 at his home in an affluent Pretoria community.

In pre-trial testimony, his lawyers told the court the shooting was a tragic mistake and Pistorius was acting in self-defense against what he thought was an intruder.

Prosecutors accuse him of premeditated murder for firing into the door, hitting Steenkamp in the head, hip and arm.