"We passionately and absolutely know that a grave and very serious injustice has taken place in Peter's case, and we won't shy away from professing that opinion as long as we can," said his father Juris Greste, speaking to reporters in Nairobi on Thursday.
Appearing at a press conference Greste's parents Loise and Juris Greste said it was unfortunate that the presiding judges of the case against their son did not consider the impact of their judgement to both the victims and family, reports Kenya’s The Star.
Juris said it has been over 200 days since his son was sentenced by an Egyptian court which has made the family so restless that they have been unable to focus on other family matters.
“Though we are allowed to see our son once for 45 minutes after every two weeks, as a family we are really doing badly and it has become difficult for us to concentrate,” Juris said.
Juris added that although the family respects the administration of law and justice, injustice took the center stage among the judges who presided over the case against Peter and his colleagues.
“This has now become a family affair and we are trying to help our son and his friends survive the ordeal of having to serve seven years in jail,” Juris said.
Loise said that though their son was currently coping well and coming to grips with the verdict, as a family through their legal counsel they are still working on ways of appealing the sentences.
The family said they have already enrolled Peter in a post-graduate degree program in social justice issues at Griffith University of Brisbane through a scholarship to try and keep him busy as they work on the appeal.
"In his mind, and in ours too, there's absolutely no way he's going to be there for the next seven years," his mother said.
Greste and two Al-Jazeera colleagues - Canadian-Egyptian Mohamed Fahmy and Egyptian national Baher Mohamed - were sentenced in June to seven years in jail for defaming Egypt and aiding banned Islamists.
Last week, Greste's family said he would appeal.
"It's a matter of going through the appeals process, and hopefully we will get to the stage where they realise that this is a mistake and free him," she added, noting she was talking about all "three boys."
The visibly distraught couple said their son was now being held in a better facility with a "little more space" compared to the tiny room he and his colleagues had been crammed into a few months ago while awaiting the verdict.
But his father Juris, who proudly held up the Peabody Award for journalism his son had won, said the impact had been terrible for the family.
The case sparked a global outcry and demands for a presidential pardon amid claims it was a politically motivated trial.
Egypt President Abdel Fattah al-Sisi has said he cannot consider a plea of clemency or a pardon until all legal proceedings have been concluded, and that includes an appeal.
Since the army ousted Islamist president Mohamed Morsi in July 2013, political unrest has reached unprecedented levels in Egypt, with more than 1400 people killed and at least 15,000 jailed in a government crackdown.
Greste, an award-winning reporter, chairs the Foreign Correspondents' Association of East Africa, which is based in Nairobi.
Greste is a dual citizen of both Australia and Latvia, and diplomats from both countries have spoken out and coordinated efforts to secure the release of the Al Jazeera team.