JUSTICE Minister Alan Shatter claimed that garda watchdog fears of bugging at its Dublin offices were based on "feelings" and not evidence.
But the controversy surrounding Mr Shatter deepened as he was accused of further undermining the independence of the Garda Siochana Ombudsman Commission.
The minister came under fire after he repeatedly called in question the basis on which GSOC launched an investigation into suspected surveillance at is offices in Dublin.
Mr Shatter was appearing before the Oireachtas Committee on Public Service Oversight to outline his actions in response to the GSOC controversy.
The minister said that he and senior officials in his department were concerned with "proportionality" when GSOC decided to investigate and said he questioned whether there was sufficient evidence to launch the probe. "There was no evidence as opposed to feelings on this issue," he said.
Mr Shatter's appearance coincided with the appointment of retired High Court Judge John Cooke to head the inquiry announced last night along with its terms of reference.
The judge is being asked to establish a chronology to set out the sequence of events "pertaining to security concerns commenced by GSOC on or about October 8, 2013".
Judge Cooke will examine all reports, transcripts, records, minutes, correspondence and documentation he deems relevant. He will also consider any oral relevant evidence from witnesses.
He will review and assess any evidence of a security breach or attempted security breach at GSOC, make recommendations aimed at improving the existing security arrangements at GSOC, and issue a report within eight weeks "or as soon as may be thereafter".
Earlier, at the committee, Mr Shatter's stance on the affair was strongly questioned by Fianna Fail's Thomas Byrne.
Mr Byrne asked: "GSOC is a fully independent body. Is it appropriate for the minister to question decisions that are taken?"
Mr Shatter also criticised GSOC's handling of a perceived security threat, an external Wi-Fi network which had connected with a device in its offices, which had turned out to be from a nearby coffee shop.
Mr Shatter said it turned out to be a Bitbuzz network in the Insomnia cafe on the ground floor of the building in Dublin's Middle Abbey Street.
"If seemed to me if they were launching an investigation they would have taken time to check out the identity of the outside network," he said.
Mr Shatter also said that 'government level equipment' suspected as being used in alleged surveillance was widely available. "I'm advised it is available on the web for €5,000," he said.
Mr Shatter said that an Irish company, RITS, provided him with information which contradicted and disputed all three main anomalies highlighted by the original investigation report, which was conducted by UK firm Verrimus on behalf of GSOC.
He added that the RITS "peer review" report was not put out to tender, which was criticised by Reform Alliance TD Lucinda Creighton. Mr Shatter acknowledged that the experts contracted by the Ombudsman's office did wrongly believe that there had already been "a breach of security systems" before they started work.
Mr Shatter also resisted calls from committee chairman Padraig Mac Lochlainn to release the full RITS report to the committee, saying he would instead provide all documentation to the High Court Judge.
However, under pressure, Mr Shatter did eventually relent to providing a summary of how the two expert reports disagree with each other.
The Justice Minister accused Richard Boyd Barrett TD of being "disappointed" the gardai were not found to be engaged in surveillance on GSOC.