A spokeswoman for Oscar Pistorius has denied allegations that the South African Olympian received acting lessons ahead of his emotional trial for the murder of girlfriend Reeva Steenkamp, Agence France-Presse reported.

The accusation came in an open letter by Jani Allan, a well-known South African columnist.

"I have it from a reliable source that you are taking acting lessons for your days in court," she wrote in an open letter posted on her website on Monday last week. "Your coach has an impossible task."

"Oscar, you are the latest in a long line of faux heroes. Like so many who preceded you, you have betrayed your people and disappointed your fans," she added.

We "deny that our client has undergone any 'acting lessons' or any form of emotional coaching", Anneliese Burgess, media manager for the Pistorius family, said in a statement on his website.

Over the course of the trial, Pistorius has repeatedly broken down and sobbed openly in the witness box as he narrated his version of shooting Steenkamp on Valentine's Day last year.

According to AFP, proceedings have continuously been disrupted by his vomiting and loud crying, with the court being adjourned a couple of times as well. His sincerity during the emotional outbursts has been questioned by some.

However, the allegations have been described as "fictitious" by Pistorius' family. Any "suggestion that Mr. Pistorius 'took acting classes' is totally devoid of any truth," they claimed.

"This type of comment makes a mockery of the enormous human tragedy involving the Steenkamp family and our client and his family," Burgess said in the statement.

Accused of shooting his girlfriend, Pistorius has said that he fired four shots through a locked cubicle door thinking Steenkamp, a 29-year-old model, was an intruder coming to attack him in the dead of night, AFP reported.

The shooting is claimed to have occurred after the couple had a fight in the early morning hours, prosecutors have argued.

His trial was postponed for the Easter break and will restart on May 5.