Oscar Pistorius' lawyers will challenge a judge's decision to allow an appeal against his negligent killing conviction by prosecutors, who want the Olympic runner convicted of murder.

Lawyer Brian Webber said Tuesday in a statement that Pistorius' defense team has applied for permission to argue against Judge Thokozile Masipa's approval of the prosecution appeal.

Masipa ruled in December that prosecutors could go to South Africa's Supreme Court of Appeal over Pistorius' culpable homicide conviction for killing girlfriend Reeva Steenkamp in 2013. The double-amputee athlete is serving a five-year jail sentence for shooting Steenkamp, but he could be moved to house arrest in August.

If the appeal court finds that Pistorius should have been found guilty of murder, as prosecutors contend, he faces a minimum sentence of 15 years in prison.