Judgment has been reserved in former minister for justice Alan Shatter's appeal against the High Court's refusal to quash some findings of the report published by Senior Counsel Sean Guerin in 2014.
Lawyers for Mr Shatter told the Court of Appeal that the report by Mr Guerin into the handling of claims by garda whistleblower, Sergeant Maurice McCabe, had directly caused him to resign from office.
The court was also told the Guerin Report directly damaged his good name and livelihood.
Mr Shatter resigned in May 2014, the day after the Guerin Report was published.
Paul Sreenan, Senior Counsel for Mr Shatter, said the subsequent report by the Commission of Inquiry chaired by former High Court judge Kevin O'Higgins had found he acted properly at all times.
He said, however, there were now two contradictory reports on the record.
Mr Sreenan told the Court that Mr Shatter was entitled to fair procedures and that right to fair procedures was breached.
Mr Shatter claims Mr Guerin should have interviewed him before reaching adverse conclusions against him.
Mr Sreenan said there was no legal constraint on Mr Shatter having the right to be heard in relation to the adverse findings against him.
He said simple fairness demanded that be done and he said a serious injustice had been done to Mr Shatter.
Mr Sreenan said as a result of the Guerin Report, Mr Shatter had been caused to become embroiled in the subsequent Commission of Inquiry.
He said the Guerin Report remained on the record and on the Government website.
Mr Sreenan said if fair procedures had been upheld by Mr Guerin, the likelihood was that the criticisms of Mr Shatter would not have been made in the Guerin Report in the first place.
He said Mr Shatter was entitled to have the relevant parts of that report quashed by the Appeal Court as the adverse conclusions against him were reached unlawfully and in breach of constitutional justice.
Mr Sreenan said it was hard to imagine a more damaging criticism of his client than that made by the Guerin Report that the minister did not seem to heed the voice of a respected member of An Garda Síochána.
The High Court found last year that the nature of the exercise undertaken by Mr Guerin in relation to Mr Shatter was limited to a consideration of Department of Justice documents, for the purpose of advising the Government if further action was needed.
The High Court judge had also criticised the proceedings by Mr Shatter as an attempt to stop the Commission of Investigation investigating his role in relation to Sgt McCabe's complaints and a collateral attack on that Commission.
Mr Shatter's lawyers said the Guerin Report made critical, damaging findings of fact against him.
These included that he did not heed the voice of Sgt McCabe; that he did not investigate complaints and that he just accepted reports from then garda commissioner Martin Callinan who was the object of Sgt McCabe's complaints.
Mr Sreenan told the court the conclusions reached by Mr Guerin impacted on Mr Shatter personally and on others' perspective in relation to the way he was fulfilling his statutory duties.
He said Mr Shatter should have been interviewed by Mr Guerin or he should have been given an opportunity to respond after draft conclusions were reached.
Mr Sreenan said a critical factor was the intention to publish the report and the intent to publish carried with it a unique risk to a person's good name.
He said the High Court judge's characterisation of the Guerin Report as a Senior Counsel's opinion was a clear mischaracterisation of what had happened.
He also said that you could not bypass fair procedures by appointing a Senior Counsel or fixing a short time for the report to be delivered.
He added that the High Court judge's finding that Mr Guerin was engaged in a review of documentation was a misunderstanding of the terms of reference.
Lawyers for Mr Guerin said this was an important case about the powers of the Government.
They said all Mr Guerin had been asked to do was carry out a "scoping report" to decide if a Commission of Inquiry was necessary.
Senior Counsel Paul Anthony McDermott said it was not correct to say all the concerns raised by Mr Guerin had been addressed by the subsequent commission.
It was still the case that there was no documentary record of consideration being given by the department to setting up the statutory inquiries Sgt McCabe was looking for.
Mr McDermott said Mr Shatter seemed to be saying that the Commission of Inquiry should have examined everybody and everything except his department.
He said the legal proceedings were a collateral attack on the commission as their purpose was to prevent the commission examining the role of the Department of Justice.
Mr McDermott said the decision to publish the Guerin Report and Mr Shatter's decision to resign were political decisions, not legal consequences of the report.
Mr McDermott said the High Court judge had described Mr Shatter's behaviour in making an allegation of bias against Mr Guerin as entirely unacceptable.
He said Mr Shatter had still not offered any explanation as to why he made this claim, which he later accepted was wrong and withdrew.
Mr McDermott said the whole point of the report was a scoping exercise to see if a Commission of Investigation should be set up.
He asked if Mr Shatter was saying the scoping exercise should have all the powers of a commission.
He said Mr Guerin was providing advice on a political decision the Taoiseach had to make.
He said the Government has never said it was unhappy with the Guerin Report or that the Guerin Report had not done exactly what it had asked him to do.
Mr McDermot said the case was not really about the powers of Mr Guerin, it was about the right of the Government and the Taoiseach to inform themselves about matters of concern and publish a report recommending the setting up a Commission of Inquiry.
The Court of Appeal this afternoon reserved its decision and will give it as soon as it can.
The President of the Court of Appeal, Mr Justice Sean Ryan, said they appreciated the importance of the issues involved for everyone.