The Government has received a letter from solicitors to Judge Brian Curtin saying that they have been instructed to commence legal proceedings against the State, the Taoiseach has told the Dáil.
However, Mr Ahern said no proceedings had been served by yesterday afternoon, and he had no details "as to the nature of the litigation he has commenced".
Judge Curtin's solicitors said they unambiguously regarded the proposals "for the impeachment process against our client" as "constitutionally flawed and inherently unfair".
But Mr Ahern said: "I am satisfied that in the light of the legal advice which I have received from the Attorney General and senior counsel the procedure which we have proposed to adopt is constitutionally sound".
He also said: "I welcome the fact that the judge is in a position to instruct the solicitors this week".
The Government proposal is that a joint committee be established to consider all the issues and submissions related to the judge and to issue a report, which would then be considered by the House before it voted on a resolution to remove Judge Curtin from office.
A simple majority of each House would be accepted.
However, the letter from the judge's solicitors suggested that submissions would not now be made to the Government but might be to the Oireachtas.
"We submit that the proper constitutional mandated process for the impeachment of our client must consist of full hearings before the Houses of the Oireachtas," the solicitors wrote.
"Further, in our opinion, Judge Curtin is entitled to a trial before both Houses of the Oireachtas as this constitutional function of both Houses of the Oireachtas cannot be delegated to any committee or other body."
Mr Ahern said amendments to the House's standing orders would be made today and the proposed resolution for the Judge's removal would be put shortly afterwards, once the President had signed the amending legislation passed last week to allow the committee to compel the judge to appear before it and to allow the committee to view the contents of Judge Curtin's computer.
The Minister for Justice would move a resolution in both Houses calling for the removal of Judge Curtin. A second resolution would then be moved to establish the joint committee to investigate the issue, and it would not sit in public unless requested by Judge Curtin.
The Green Party leader, Mr Trevor Sargent, asked for the House to be "absolutely clear on the constitutionality and the probity of what is being proceeded with in relation to the judge".
He said the comments by members of the media that "this may never get off the ground" should be responded to.
Mr Ahern said: "The process of removal from office is a matter for this House and the Seanad. It is exclusively within the constitutional sphere, not a matter for Government."
He added: "The Houses of the Oireachtas are in exclusive control of the process, and nothing can happen to that process without the approval of the Houses".
