A powerful parliamentary watchdog is taking legal advice on whether a dossier of allegations about tax evasion involving senior politicians should be investigated by police.
The claims are carried in a file running to more than 100 pages, including official records, which was posted by a serving senior civil servant to members of the Public Accounts Committee during the week.
It is understood to involve allegations that secret offshore bank accounts were used by several well-known former politicians, allowing them to evade tax on at least hundreds of thousands of euro over many years.
It is further claimed that some high-ranking politicians - including current representatives - knew about the alleged wrongdoing but that it was never fully investigated or inquiries into the offshore arrangements were blocked.
Sean Fleming, Fianna Fail's public spending and reform spokesman, who sits on the parliamentary watchdog, confirmed a former judge is also named in the dossier.
"We are taking legal advice through the Public Accounts Committee next week," he said.
"If the legal advice tells us that there are allegations of criminal wrongdoing in this matter, we are obliged by law to hand that matter over to the Garda Siochana for investigation and maybe the Director of Corporate Enforcement as well."
The allegations were handed over under the Protected Disclosures Act, which was only enacted in July to give protection to whistleblowers passing on evidence to relevant authorities in the public interest.
Mr Fleming said the whisleblower now had "cast iron" protection to pass on the information, which they would not have had in the past.
The serving civil servant has been involved in the area being probed for a long time, and claims the allegations were never fully investigated, including by former Government ministers.
There are at least four or five prominent names involved, some of whom are now dead.
The allegations stretch back over a number of decades.
The legal advice is expected to be discussed in a private session of the Public Accounts Committee next week.
Mr Fleming said if there is clear evidence of criminal wrongdoing they will formally ask the Garda to launch an investigation, otherwise the watchdog itself may pursue the evidence.
Health Minister Leo Varadkar said he was aware that legal advice was being sought on the dossier.
"Let me be very clear about this - tax evasion is not acceptable," he said.
"When someone is engaged in something like shoplifting they may steal from one or two people.
"Tax evaders steal from four and a half million people and there can be no tolerance of it."