Michael Masutha said a decision by the parole board at Kgosi Mampuru prison in Pretoria to release Pistorius just 10 months into a five month sentence for manslaughter was "premature" and asked for a review of his case.
It means the athlete, previously known as the Blade Runner for the carbon fibre prosthetics which he used to compete on, could now remain behind bars until the state appeal over his acquittal of the charge that he murdered Steenkamp deliberately.
For the Steenkamps, there is no doubt what the verdict should have been.
"He killed her. He admits he killed her," June Steenkamp said in an emotional interview with Australia's Channel Seven.
"She is dead after [Pistorius made] sure she was dead. Why didn't he just let her walk away?"
He husband said he never believed Pistorius' claim that he fired four times at the model through a locked toilet door at his home on St Valentine's Day 2013 because he thought she was an intruder.
"What actually came out in court is not the truth," he said. "We know what we heard there is not right."
He pointed to the evidence of witnesses who said they heard a woman screaming from up to 200m away before the shots were fired.
"People actually heard the screams and when he realised that had happened he couldn't stop. He had to carry on until it was finished."
Judge Thokozile Masipa, who heard the high-profile and long-running case at Pretoria High Court last year ruled however that the state's case against him was based solely on circumstantial evidence and it had failed to prove its theory of murder "beyond reasonable doubt".
Barry Steenkamp said even if the appeal at the Supreme Court resulted in a murder conviction, their ordeal would not be over.
"It is not finished - not finished I feel by a long way - and I can only give you my feelings after the final verdict," he said.
"If the outcome is going to be a longer sentence, are we going to feel better? I don't know.
"All we want is the truth to come out in the real justice side of the whole scenario."
June Steenkamp, who sat through almost the entire trial and has previously spoken of her pain when the athlete appeared to look right through her, said she simply wanted to be sure he understood the scale of their loss.
"All I want you to realise is that you have ruined our lives. You've taken her life, her possible marriage, or having a baby - our grandchild," she said.
"You've taken her career away... You've taken the most precious thing out of our lives."
