Prosecutors to appeal Oscar Pistorius six-year sentence

South African prosecutors are appealing the six-year jail sentence handed down to Oscar Pistorius for the murder of his girlfriend Reeva Steenkamp.

The prosecutors are pushing for a longer sentence for Steenkamp's Valentine's Day murder in 2013.

Former Paralympian Oscar Pistorius. Source: 7News
Former Paralympian Oscar Pistorius. Source: 7News
Oscar Pistorius during his trial. Source: 7News
Oscar Pistorius during his trial. Source: 7News

"(The National Prosecuting Authority) has decided to file an application for leave to appeal," it said in a statement.

The NPA said the sentence was "shockingly too lenient".

Pistorius has always maintained it was a case of mistaken identity when he shot the model behind a bathroom door.

He has long claimed he thought she was an intruder inside his gated community home in Pretoria.

Reeva Teenkamp and Oscar Pistorius. Source: 7News
Reeva Teenkamp and Oscar Pistorius. Source: 7News

The 29-year-old was sent to Pretoria's maximum security prison a fortnight ago after he was sentenced.

He had been facing a minimum 15 years behind bars under South African law, but Judge Thokozile Masipa said the "fallen hero" should serve a shorter sentence.

She took into account Pistorius's remorse and rehabilitation when sentencing.

Oscar Pistorius. Source: 7News
Oscar Pistorius. Source: 7News