Mental health experts at the murder trial of Oscar Pistorius have concluded he was not mentally ill when he shot his girlfriend Reeva Steenkamp.

The trial in South Africa resumed this morning after being suspended last month so Mr Pistorius could undergo psychiatric tests to determine whether mental illness played any part in his actions.

A psychiatric panel and a psychologist said the Olympic and Paralympic sprinter is fit to stand trial.

"Mr Pistorus did not suffer from a mental illness or defect that would have rendered him criminally not responsible for the offence charged," said state prosecutor Gerrie Nel, reading from the psychologist report.

Mr Pistorius argued that a "generalised anxiety disorder" contributed to him shooting the 29-year-old model on Valentine's Day last year at his Pretoria home.

Mr Pistorius denies killing Ms Steenkamp after an argument, as suggested by prosecutors, and insists he shot four times at the toilet door she was behind, in self-defence against what he thought was an intruder.

Both Mr Nel and defence lawyer Barry Roux accepted the findings of the panel after 30 days of evaluation.

Mr Pistorius could face a life sentence if found guilty of the shooting.