Oscar Pistorius accused of intimidating Reeva Steenkamp's friend Kim Myers in court

Reeva Steenkamp and friend Kim Myers at a party (INSTAGRAM)

Oscar Pistorius has been accused of approaching a friend of Reeva Steenkamp in the middle of his murder trial and whispering "How can you sleep at night?" in a sinister tone.

Kim Myers, one of Ms Steenkamp's closest friends and a potential witness for the prosecution, claimed the athlete made the comment under his breath as he walked past her.

Her lawyer, Ian Levitt, told The Independent: "There are witnesses who can confirm this, a reporter sitting behind Kim saw Oscar approach her, and she was horrified. There is no reason reason why my client would lie about this."

The athlete's lawyer, Brian Webber, denied the incident took place, saying: "I'm not even going to dignify that with a comment. It's grossly untrue. He never said anything of the sort."

Separately, the athlete told reporters in Pretoria: "I haven't spoken to them for a year and a half. I walk past them in the corridors and hold doors open for them but they don't look me in the eye."

But Mr Levitt insisted Pistorius made the comment "in the presence of some witnesses" and his denial is "obviously a lie" because he doesn't want to take responsibility.

He added: "Again, this shows he is a man who does whatever he wishes, regardless of the consequences. To think he would approach a potential witness in a murder trial and to do this is unfathomable."

Mr Levitt said Ms Myers was "disturbed" by the incident and her mother, Desi, is "furious" but the family will continue to attend the trial in support of Ms Steenkamp.

The 29-year old model and law grauduate was very close to the Myers family and moved into their Johannesburg home after leaving her hometown of Port Elizabeth in South Africa. Kim, her sister Gina, and parents, Desi and Cecil Myers, were all on the prosecution's potential witness list.

Meanwhile, South Africa's National Prosecuting Authority confirmed it had received a report about the alleged incident but said it cannot get involved in the matter from a legal standpoint.

"In law we cannot get involved, "NPA spokesman Nathi Mncube said. "The lawyer that made the report was advised to deal with the matter as they deem fit."

Pistorius is accused of murdering his girlfriend following a domestic dispute in the early hours of Valentine's Day last year. He claims he shot and killed his girlfriend in a case of mistaken identity, thinking she was an intruder.

South Africa does not have trial by jury, meaning Judge Thokozile Masipa will decide Pistorius' fate with the help of two assessors.

The murder trial continues.