The Government has agreed the terms of reference for the Commission of Investigation to be conducted by Mr Justice Nial Fennelly.
The main issues to be investigated are the operation of telephone recording systems to record calls other than 999 calls at a large number of garda stations over many years.
The specific implications of the taping related to the garda investigation into the death of Sophie Toscan Du Plantier in Co Cork in December 1996 will be investigated.
Whether these recordings "disclose any evidence of unlawful or improper conduct by members of An Garda Síochána in connection with that investigation" will then be probed.
Finally, the sequence of events leading up to the resignation of Martin Callinan as garda commissioner will also be investigated.
This includes the letter dated 10 March sent by Mr Callinan to the Department of Justice.
The Commission of Investigation is to report back before the end of this year.
The Government is due to receive a report on the garda recordings from the Acting Garda Commissioner Noirin O'Sullivan.
Responding to queries today about whether or not it will be published, a garda spokesperson said correspondence between the Minister for Justice and the Garda Commissioner is confidential.
The Oireachtas Justice Committee will meet tomorrow morning to discuss the Commission of Investigation's terms of reference.
Members will also discuss their next course of action.
Ian Bailey's solictor, Frank Buttimer, said they had read the Commission's terms of reference and are evaluating them.
He said they will give a more considered response in the coming days when they have had an opportunity to consider the full impact of them.
Earlier, Minister for Public Expenditure and Reform Brendan Howlin said the terms of reference would be "comprehensive".
He said he hoped the inquiry would be carried out as speedily and expeditiously as possible.
Mr Howlin also said recordings in prisons would also be included in the terms of reference.
Two weeks ago, the garda commissioner stepped down before it emerged that telephone conversations to and from garda stations were recorded.
A week ago, it was revealed that recordings within the prison system also took place.
Minister for Children Francis Fitzgerald has said the terms of reference are the most comprehensive that have ever been set for an investigation of this nature.
Speaking on RTÉ's News At One she said the Commission of Investigation should be effective, with a report expected to be delivered before the end of the year.
She said the Government wants it to be efficient and cost effective. "We want a report by the end of year, that's our request of Mr Justice Fennelly.
"We have very comprehensive terms of reference, in fact I would say the most comprehensive terms of reference a commission like this has ever got. We want to get at the truth," she said.
ICCL disappointed at narrowness of terms
The Irish Council for Civil Liberties has expressed its disappointment at what it called the narrowness of the terms of reference.
ICCL Director Mr Mark Kelly said: "This is a missed opportunity. Regrettably, the initial Terms of Reference offered to Mr Justice Nial Fennelly effectively restrict him to examining allegations of illicit taping in garda stations and, possibly, in prisons.
"Once again, the Government has failed to grasp the nettle of requesting the judge to examine the full range of garda accountability issues that have come to light in recent weeks and months.
"This is very far from being the 'comprehensive' inquiry that had been mooted and the ICCL hopes that the Oireachtas will take the opportunity to amend the judge's Terms of Reference before they are formally approved."
Meanwhile, Fine Gael MEP Jim Higgins has forwarded information provided to him by two gardaí whistleblowers to the Minister for Justice Alan Shatter.
Speaking on Raidió na Gaeltachta this morning, Mr Higgins stated that the information provided to him about issues pertaining to An Garda Síochána by the two members of the force, one still serving and one retired, was "frightening".
However, he maintained that he cannot provide any more information about the matter until it has been fully investigated.