Oscar Pistorius walks on stumps in court

Oscar Pistorius has walked on his stumps in court as part of his defence team's argument that the double-amputee athlete, convicted of murdering girlfriend Reeva Steenkamp, is a vulnerable man who deserves leniency when he is sentenced.

Defence lawyer Barry Roux asked Pistorius to remove his prostheses and the former track star then hobbled in front of Judge Thokozile Masipa, who will deliver the sentence after hearings end this week.

He appeared unsteady at times, and the demonstration drew gasps from some onlookers in the courtroom.

Oscar Pistorius walks across the courtroom without his prosthetic legs during the third day of his hearing for a resentence at Pretoria High Court. Photo: Getty Images

The former track star, who had changed from a suit into athletic clothes for the demonstration, then returned to a bench where he sat alone, head bowed.

Pistorius was on his stumps when he fatally shot Ms Steenkamp through a toilet cubicle door in his home 2013.

He testified at his murder trial that he felt vulnerable and thought an intruder was in the house.

Oscar Pistorius in court. Photo: Getty Images

Prosecutors have said Pistorius intentionally killed Ms Steenkamp after an argument.

Chief prosecutor Gerrie Nel later spoke, countering the defence argument that Pistorius is a "broken man" because of the grief from killing Steenkamp and the trauma that followed as the world focused on his case.

Nel referred to the emotional testimony a day earlier of Barry Steenkamp, father of the victim.

TV host and model Reeva Steenkamp.

"If you ever want to talk about a broken man, we saw a broken man there," Nel said of Barry Steenkamp.

Pistorius is living under house arrest after initially serving one year of a five-year prison sentence for manslaughter for shooting Ms Steenkamp multiple times in 2013.

That conviction was overturned last year by an appeals court, which convicted Pistorius of the more serious charge of murder.

Masipa, who initially acquitted Pistorius of murder, will decide the new sentence. The hearing is scheduled to run through to Friday.

South Africa has a minimum sentence of 15 years in prison for murder, although a judge can reduce that in some circumstances.

Earlier on Wednesday, defence lawyer Roux said there are misconceptions over Pistorius' murder conviction as he asked Masipa for leniency.

Roux said "substantial and compelling circumstances" existed that would allow the judge to deviate from the minimum term of 15 years in prison.

Roux's plea to Judge Masipa followed the testimony of the final witness at the hearing, a cousin of Ms Steenkamp, who accused Pistorius himself of not giving the "true version" of the shooting.

The cousin, Kim Martin, also criticised Pistorius for not testifying at this week's sentencing hearing but agreeing to a television interview that will be broadcast after the hearing ends.

"I think it's very unfair to want to talk to the world about your version when you had the opportunity in court to do so," Martin said.

AP