Barry Steenkamp revealed he has tried to imagine the horrific moment of his daughter's death, and said: "Oscar has to pay for what he did."
He told the court that, as a Christian, he knows he has to forgive Oscar Pistorius for his crime: "June (Reeva's mother) is a Christian, so am I but I don't really go to church. June has forgiven. She feels it's right in her heart to forgive Oscar."
He went on: "But...forgiving like that, it still does not exonerate you from the crime that you committed.
"He has to pay for that.
"It's been very difficult for me to forgive. But I feel the same, that Oscar has to pay for what he did. He has to pay for it. And that's all I can say.
"Most probably the time will come when I want to talk to Oscar in private, not now, at a later stage, I would like to talk to him, yes."
Oscar Pistorius, the double-amputee, who also competed at the 2012 London Olympics, is currently under house arrest after initially serving one year of a five-year prison sentence for manslaughter for shooting Reeva Steenkamp on St Valentine's Day 2013 at his Pretoria house.
That conviction was overturned last year by an appeals court, which convicted Pistorius of the more serious charge of murder.
Pistorius shot model and reality TV star Reeva Steenkamp several times through a toilet door. He claimed in his trial that he thought his house had been broken into, and that he opened fire in the belief that an intruder was hiding behind the door.
Pastor Marius Nel testified for Pistorius' defence and said that he had been in contact with schools who want him to help disadvantaged children with sports training.
The pastor also said he had visited Pistorius after he was jailed for the earlier manslaughter conviction and found him to be a "broken" man.
The hearing is scheduled to run until Friday.
