The Government has been urged to set up a new judge-led inquiry into allegations that "rogue" officers were unofficially running criminals as informants.
Sinn Féin's Martin Kenny said most of the allegations, some of which were first raised publicly two years, were already with the Department of Justice.
The Sligo-Leitrim TD claimed two officers with young families accidentally discovered senior gardaí had been aware of a threatened attack on their homes by a criminal gang.
He said the information had been withheld from the gardaí for weeks.
Mr Kenny claimed one of the gang members was working off the books as an informant for other officers but had also been reporting his criminal activity to the official Garda informant system, the Covert Handling of Intelligence Sources known as Chis.
The TD said he also had serious concerns about the disappearance of Pat Heeran, 48, from Aughavas, Co Leitrim in 2011.
Mr Kenny said that between the time of his disappearance and gardaí launching an investigation into a suspected abduction, the man's house had been broken into and the potential for forensic evidence had been lost.
"It is now known that a garda informant was among the last people to be in Pat Heeran's company before he disappeared," the Sinn Féin TD said.
"The question is was the protection of informants put before the proper investigation into the disappearance?."
Mr Kenny raised the whistleblower claims in the Dail during the debate into the O'Higgins Commission which upheld a catalogue of bad policing in the Cavan and Monaghan district after a lengthy battle to expose it by Sergeant Maurice McCabe.
"At the outset I want to clearly state that in my area of Leitrim, as in other places, the vast majority of guards are doing their job honestly and diligently," Mr Kenny said.
The Sinn Féin representative said he had been given information from both serving and former gardai.
"Central to the many events I will now outline is the allegation that gardaí were engaging informants who were active criminals which was in breach of the rules of the Chis programme," he said.
"Another allegation is that some gardaí were running their own informants outside of the official Chis programme.
"The third allegation is that some rogue gardaí have used informants, or criminals they have control over, to set up and entrap people for crimes and then prosecute these people."
Meanwhile, Tánaiste and Justice Minister Frances Fitzgerald defended Garda Commissioner Noirin O'Sullivan's handling of allegations that two officers wrongly claimed Sgt McCabe told them he raised his concerns about policing out of malice.
She said it was correct for the Garda chief to wait until the O'Higgins Commission had finished its work before calling in the Garda Ombudsman.
"What is being suggested is the Garda Commissioner should, while the Commission was still going on, have launched her own investigation into certain matters that were before the commission, before Mr Justice O'Higgins had made his findings about the matter," the Tánaiste said.
"It is easy to see how that would have been portrayed as a gross interference with the work of the Commission."
She added: "What we are left with is that, whatever the reality of what actually happened, there is understandable public concern at allegations that members of An Garda Siochana may have fabricated an account of a meeting to cause damage to a colleague.
"The Garda Commissioner has rightly asked me to refer this matter to the Garda Siochana Ombudsman Commission."