JOHANNESBURG: The family of Oscar Pistorius's slain girlfriend Reeva Steenkamp on Monday prepared to hold a funeral service for the 29-year-old model, as her bereaved mother pleaded for answers about the death of "the most beautiful person who ever lived".

The former cover girl, who was shot dead at Pistorius's luxury home in Pretoria on Valentine's Day, will be cremated on Tuesday in her home town of Port Elizabeth, in a private ceremony for family and friends.

Pistorius, a double amputee who became a sporting hero to millions when he competed at the Olympics last year, has been charged with killing Steenkamp and will appear in a Pretoria court on Tuesday for a bail hearing.

In an interview published on Monday, Steenkamp's mother described her death as "horrendous."

"Why my little girl? Why did this happen? Why did he do this?," June Steenkamp told the Times of South Africa. "What for?"

"She had so much of herself to give and now all that is gone. Just like that, she is gone... In the blink of an eye and a single breath, the most beautiful person who ever lived is no longer here."

"All we have is this horrendous death to deal with... to get to grips with. All we want are answers... answers as to why this had to happen, why our beautiful daughter had to die like this."

More than 100 people are expected to attend an hour-long memorial service Tuesday for Steenkamp, a law graduate who had been going out with the 26-year-old Pistorius since late last year.

Well-wishers have already begun placing bouquets of flowers outside the family home.

On Saturday a celebrity television show aired haunting footage of Steenkamp speaking about the need to leave a positive mark on life, words laden with unintended poignancy after her death.

"Not just your journey in life, but the way that you go out and make your exit is so important, you have either made an impact in a positive way or a negative way," Reeva Steenkamp said.

Her uncle Mike Steenkamp said the family had been overwhelmed with offers of help and sympathy.

"We have received a lot of condolences from all over South Africa and around the world as well. We have received a lot of support."

Police says Steenkamp was shot four times in the early hours of Thursday by a pistol owned by Pistorius and died of her wounds at the scene.

His family has insisted that the evidence will refute "any possibility of a premeditated murder or indeed any murder at all".

Defence lawyers are expected to argue at Tuesday's hearing that there are "exceptional circumstances" for Pistorius to be granted bail, a request that will be opposed by the state.

That request means the hearing is likely to offer more details about what happened in the early hours of Valentine's Day at Pistorius's upmarket home in a gated estate in the South African capital.

Unconfirmed reports have suggested Pistorius mistook Steenkamp for an intruder, while other reports said she was beaten with a cricket bat before being shot multiple times.

Pistorius, who broke down sobbing in his first court appearance on Friday, has built up a powerful team of lawyers, medical specialists and public relations experts for his defence.

Stuart Higgins, a former editor of British tabloid The Sun, whose lengthy list of clients includes British Airways, Chelsea FC and Manchester United football club, will be handling public relations in the case.

One of the lawyers, Kenny Oldwage, acted for the driver in a 2010 accident that killed former president and anti-apartheid icon Nelson Mandela's great-grandchild Zenani. The driver was acquitted.

Pistorius is a national icon who inspired people around the world when he became the first double amputee to compete against able-bodied athletes in the 2012 London Olympic Games.

The events of February 14 have put Pistorius's career on hold, forcing him to cancel races in Australia, Brazil, Britain and the United States between March and May.

"I have decided that following these tragic events that we have no option but to cancel all future races that Oscar Pistorius had been contracted to compete in, to allow Oscar to concentrate on the upcoming legal proceedings," manager Peet van Zyl said.

Sponsors and partners are in the meantime maintaining their contractual commitments awaiting the outcome of the legal process, Van Zyl said in a statement.