State prosecutor Gerrie Nel has questioned the events leading up to Reeva Steenkamp's death during closing arguments in Oscar Pistorius's murder trial at the High Court in Pretoria today.

The Paralympic champion is accused of murdering his girlfriend by firing four shots through a bathroom door at his home in the early hours of Valentine's Day last year.

The double amputee denies murder by claiming that he mistook the South African model for an intruder when he fired the shots, but the prosecution argues that Pistorius killed Steenkamp after a furious row.

While delivering his closing speech, Nel told the court that Pistorius's version of events leading up to the shooting are "ridiculous", and questioned why Steenkamp would have taken her mobile phone with her to the toilet at 3am.

Earlier today, Nel also described Pistorius as a "deceitful witness".

After two days of closing arguments from both prosecution and defence, the judge could take around a month to consider her verdict.