Oscar Pistorius's siblings appeared in a number of televised interviews on Monday ahead of the South African athlete's sentencing over his girlfriend Reeva Steenkamp's death.

"It's obvious we can't speculate what the outcome will be tomorrow. It has been a taxing 20 months... and no doubt tomorrow will also be difficult," said Carl Pistorius, Oscar Pistorius's older brother in an interview with the eNCA television channel.

Pistorius's younger sister, Aimee said the family is still struggling to accept Steenkamp's death as she had become a part of their family since the couple were together.

"It's important for us that they [Steenkamp's family] know that she was very much cared for and loved and accepted as part of our family in the short time that she was with us. She had a wonderful charisma, [it was] easy to fall in love with her," said Aimee.

It is the first time that the Pistorius siblings have released a public statement following Steenkamp's death.

The paralympian could face a sentence of up to 10 years or be placed under house arrest on Tuesday when High Court judge Thokozile Masipa releases the final sentence.

Pistorius was acquitted last month of murder but found guilty of culpable homicide – a crime that carries a penalty varying from a fine to a prison term.

While the prosecution is pushing for a 10-year-sentence, the defence is requesting three years of "correctional supervision," which is similar to being put on house arrest.

The defence has further expressed that Pistorius can do 16 hours of community service a month if put on house arrest.

The Pistorius siblings remain hopeful and vowed to stand by their brother on the eve of the sentencing.

"We have a strong faith and we stand strong," said Carl.