Prosecutor Gerrie Nel outlined his objections to the culpable homicide verdict and sentence against the Olympic runner, saying Judge Thokozile Masipa erred in her interpretation of the law. Masipa, who presided over the Pistorius trial, will also decide whether the case can be heard at the Supreme Court of Appeal.
In October, Masipa convicted Pistorius of the lesser charge of culpable homicide and sentenced him to a five-year prison term. He could be released from prison to be held under house arrest after 10 months.
"There is a very good prospect that we may convince an appeal court that the shortest possible incarceration in a case like this, my lady, is shockingly inappropriate," Nel said, addressing Masipa in the same courtroom where the murder trial was conducted. If the right to appeal is granted, Nel said he will argue for a harsher sentence.
The double-amputee athlete is serving his sentence in a Pretoria prison and was not in court.
Pistorius fatally shot Steenkamp in his home on Valentine's Day, last year. He said he thought a dangerous intruder was in the house; prosecutors allege he killed his girlfriend after an argument and are now appealing his acquittal of murder.
In an argument that continued for over an hour, Nel cited a number of complex cases which resulted in a retrial. This can only happen in specific circumstances because South African law, like U.S. law, does not allow an accused to be tried twice for the same charge.
Pistorius' defence attorney, Barry Roux, argued against allowing an appeal on either the conviction or sentence.
If an appeal is granted and Pistorius is convicted of murder, he would face a minimum of 15 years in prison.