The Court of Appeal previously unanimously ruled in Alan Shatter's favour
The Supreme Court is being asked to overturn Alan Shatter's successful appeal against parts of the Sean Guerin report.
Two years ago, the Court of Appeal decided Mr Shatter should have been given a right of reply to criticisms of his handling of Garda whistleblower allegations.
In November 2016, the three-judge Court of Appeal unanimously ruled in the former minister's favour.
They agreed he should have been asked for his version of events before Sean Guerin concluded that he hadn't adequately handled allegations of Garda misconduct in the Cavan/Monaghan division.
He was subsequently granted a declaration to say that Mr Guerin acted in breach of the requirements of natural justice in coming to the conclusions he did in a report that led to Mr Shatter's resignation as Minister for Justice the day after its publication in 2014.
Before the Supreme Court this afternoon, Mr Guerin's barrister Paul Gallagher said his client was asked to carry out a scoping exercise by the Government of the time.
He said for the author of such a commissioned report to be subjected to judicial review creates "very significant issues" and could impede the flow of information to help the Government make informed decisions.
The hearing continues.