Oscar Pistorius must pay for the crime of murdering his girlfriend Reeva Steenkamp, which has devastated her family, her father told a South African court yesterday.

The 29-year-old Paralympian gold medallist faces a minimum 15-year jail term after his manslaughter conviction for the 2013 killing, for which he originally received a five-year sentence, was upgraded on appeal.

Called to testify by the lead state prosecutor in Pistorius's sentencing hearing, a tearful and trembling Barry Steenkamp said forgiving the runner was very hard.

"It just devastated us, I ended up having a stroke... I just don't wish that to anybody in this world," the 73-year-old said. "He has to pay for his crime."

Steenkamp said he and wife June had relied financially on their daughter, and he had hurt himself to try to relive the pain that his daughter went through: "I jabbed myself with needles."

He asked the court to allow pictures of his daughter to be shown to the world as a deterrent to would-be killers.

But prosecutor Gerrie Nel said Pistorius has shown no remorse for shooting and killing Steenkamp when he fired four shots through a locked toilet door in his Pretoria home.

Nel also said he had had temper tantrums while serving his sentence.

The case has prompted a fierce debate in a country beset by high levels of violent crime against women. Some rights groups have said the white athlete has received preferential treatment.