Oscar Pistorius on his stumps, holding a gun, would have been a "formidable" person, the High Court in Johannesburg heard on Friday.

The physical demonstration of a vulnerable man walking on his stumps was not an accurate reflection of what happened on the night he shot and killed Reeva Steenkamp, prosecutor Gerrie Nel told Judge Thokozile Masipa.

He was referring to Pistorius being made to walk across the courtroom during his sentencing proceedings in the High Court in Pretoria in June. He did so at the request of his lawyer Barry Roux. Pistorius cried, appeared unsteady and had to use the furniture to keep his balance.

Nel was applying to Masipa for leave to appeal the six-year jail term for murder she imposed on Pistorius on July 6.

"A physical demonstration at night would have been different. In the dark, walking down the passage with a gun, a lethal firearm loaded with ammunition that would devastate. Such a person is formidable," said Nel.