Garda Commissioner Martin Callinan has said he will be taking legal advice over the proposed appearances of two garda whistleblowers at the Public Accounts Committee next week.
Mr Callinan said speaking at the PAC is not the proper forum for gardaí to make serious or criminal accusations against colleagues.
He said using that platform to discuss such matters would have an adverse effect on discipline within the force.
Commissioner Callinan defended the force's handling of the penalty point controversy and said that nobody has provided any evidence of corruption and malpractice.
The identity of the serving garda whistleblower was revealed at the committee today.
Garda Sergeant Maurice McCabe is understood to be serving in the midlands.
The identity of retired garda John Wilson had been known for some time.
Commissioner Callinan said he should have the opportunity to deal with this situation in advance of these people coming in.
These individuals had limited access to information and may be misguided, he said.
He also said that he had not seen the information that was provided to the committee.
The commissioner said this was not about circling the wagons, but that it was about the fundamental principle of the control and discipline of An Garda Síochána.
He said these issues should be dealt with by him at other forums and that perhaps the Director of Public Prosecutions should be involved.
The commissioner also said it is extraordinary that there are just two individuals making these allegations.
Mr Wilson said he and his colleague are standing over their allegations.
He confirmed that he had submitted documents to the committee and said he would be seeking legal advice following the statement of Commissioner Callinan.
The Transparency International Ireland group, which provides support for garda whistleblowers, said Commissioner Callinan should withdraw the threat of legal action against the two whistleblowers.
Its chief executive John Devitt said: "The commissioner should be aware that gardaí are legally entitled to report concerns of apparent wrongdoing within An Garda Síochána to members of the Oireachtas.
"It's disappointing that he is now threatening disciplinary action against a serving garda for availing of that legal right."
10,000 fixed charge notices terminated annually
In his opening address, the commissioner said the penalty point system was not a revenue generation measure and that just over 10,000 fixed charge notices are terminated every year.
This equates to two cancellations per week per garda district, which can have up to six stations in it, or 2.6% of the 1.46 million issued, he said.
The commissioner also said that even when a penalty notice is issued, it is not mandatory that a prosecution or a payment should follow.
The use of discretionary powers has served gardaí well since the foundation of the State, he said.
Commissioner Callinan also told the committee gardaí have introduced a number of measures that have strengthened procedures around the cancellation of penalty point notices, as well as greater oversight and auditing of the system.
He said that two internal audits in November/December of last year showed 100% of these cancellations were carried out within policy.
The commissioner said that no thread of evidence has been found to date and nobody has provided any evidence of corruption and malpractice.
PAC member Derek Nolan asked if it was corruption if a garda cancelled penalty points for a family member.
The commissioner said he does not expect any member of the gardaí to do favours for their friends.
He said he expects that everybody making those decisions makes them for the right reason and he would expect all of his officers to act fairly.
The PAC is investigating complaints from two garda whistleblowers about what they claim is a practice in the force of routinely cancelling penalty point notices.
In recent days, the committee has been presented with fresh material understood to come from Sinn Féin TD Pádraig Mac Lochlainn.
At a private meeting last night, the committee decided to invite one of the whistleblowers to appear either in public or in private session to be questioned about the allegations.
PAC chairperson John McGuinness said he has met one of the whistleblowers in relation to the controversy.
Mr McGuinness said he is satisfied as to the whistleblower’s bona fides and said he has a story to tell.
He said the man alleges the penalty point issue is a much more widespread problem than has been documented.
Mr McGuinness also said he was concerned about his position as a serving garda and is experiencing serious difficulties in his job.