Masipa presided over Pistorius’s lengthy trial, and South African law empowers the trial judge to grant or reject applications to appeal their own judgements.

After Masipa’s decision, the prosecution is now left with the option of directly petitioning the Supreme Court of Appeal to ask it to toughen the sentence.

The prosecution had been pushing for a longer sentence against the fallen 29-year-old sprint star over the 2013 murder of Reeva Steenkamp.

“The sentence of six years is shockingly lenient and disturbingly inappropriate,” prosecutor Gerrie Nel argued in court.

Pistorius shot Steenkamp, a model and law graduate, in the early hours of Valentine’s Day in 2013, saying he mistook her for a burglar when he fired four times through the door of his bedroom toilet.

At his sentencing in July, Masipa listed mitigating factors for ordering Pistorius to serve less than half the minimum 15-year term for murder, including the athlete’s claim he believed he was shooting an intruder.

“I’m of the view that a long term of imprisonment will not serve justice,” Masipa said.

But Nel argued that the six-year sentence was flawed and that it should be appealed.

“Another court may find that this court misdirected itself,” said Nel.

Masipa was also the judge who had originally convicted Pistorius of the lesser charge of culpable homicide, the equivalent of manslaughter, in 2014.

An appeals court upgraded his conviction to murder in December last year.

Pistorius’s defence said it was an “insult” to suggest that the court’s sentencing had been flawed and that it was time the case came to a close.

“Enough is enough. What does the state want?” defence lawyer Barry Roux said.

“This case has been exhausted beyond a point of any conceivable exhaustion,” he added, accusing the prosecution of sending Pistorius “like a ping pong ball between courts”.

The prosecution still has recourse.

“Any party who has to apply to the trial judge for permission to appeal and is unsuccessful, the option is open for them to petition the Supreme Court of Appeal,” said Stephan Terblanche, a law professor at the University of South Africa.

Terblanche said the Supreme Court which consists of five judges would study the grounds of appeal and those opposing the appeal, and make a decision without conducting a hearing.

Pistorius, who pleaded not guilty at his high-profile trial, has always denied killing 29-year-old Steenkamp in a rage, saying he was trying to protect her.

South African media reports earlier this month said that Pistorius had been put on suicide watch following mysterious wrist injuries.

The year before he killed Steenkamp, Pistorius – known as the Blade Runner –-became the first double-amputee to race at Olympic level when he appeared at the London 2012 Games.