A South African court has ordered that Olympic track star Oscar Pistorius is to undergo evaluation for mental illness.

Judge Thokozile Masipa ruled that such an evaluation would ensure that Mr Pistorius would get a fair trial.

Judge Masipa said the court would hand down the details of the assessment next Tuesday, adding it would be "preferable" for Mr Pistorius to undergo the evaluation as an outpatient.

The athlete is accused of murdering his girlfriend Reeva Steenkamp on Valentine's Day last year.

The defence claims Mr Pistorius suffers from "general anxiety disorder".

Defence psychiatrist Meryll Vorster yesterday told the court that Mr Pistorius's anxiety would have given him a heightened fear of crime.

Mr Pistorius's lawyers have sought to portray the world-famous athlete as almost manically obsessed with safety after a difficult childhood and in the face of high crime levels in South Africa.

The star sprinter claims he mistakenly shot Ms Steenkamp through a locked toilet door believing she was an intruder in his upmarket Pretoria home.