The Labour Party leader last night stood over his claim that the Government was pursuing a citizenship referendum because Fianna Fáil's voter research had identified immigration as a major election issue.
Fianna Fáil's official spokeswoman accused Mr Pat Rabbitte of "absolute fabrication" after he said in the Dáil that voter research by US consultants engaged by Fianna Fáil placed immigration "17 points ahead of health" as an election issue.
Labour's official spokesman expressed surprise at the stance adopted by the Fianna Fáil spokeswoman and said Mr Rabbitte was standing by his remarks.
The Fianna Fáil spokeswoman said: "We carry out research from time to time. This issue has not been highlighted in our research."
She said she was absolutely certain about that.
While Fianna Fáil has been a client of the US consultancy Shrum Devine & Donnelly, the spokeswoman said, the party had not engaged any US consultancy to carry out voter research for it.
The two parties clashed after the Tánaiste, Ms Harney, said no date had been set for the referendum but indicated a preference for conducting the poll on the same day as the local and European election on June 11th.
"Many would be of the view that we are having an election anyway, and it makes more sense to have it on that occasion than to have it during the presidential election, if there is one," she said.
While Ms Harney had no doubt that the referendum would wtir up "undesirable feelings", she said there was an onus on all politicians to ensure "racism does not take hold in Ireland to ensure that the campaign is conducted to the highest possible standards".
The Cabinet discussed the referendum at its weekly meeting yesterday, but a Government spokesman said he did not know whether there was agreement on the detail of proposal to be put before voters.
Mr Rabbitte sought to shift the focus of the debate to claims by the masters of the Dublin maternity hospitals that they were being made "scapegoats" for the Government decision to seek a referendum. Ms Harney said she was not certain what had happened at a meeting between the masters and the Minister for Justice, Mr McDowell.
Mr McDowell has said the masters "pleaded" with him for Government action to do something about the large numbers of foreign nationals presenting late in their pregnancies to give birth in Ireland.
The masters subsequently denied that they had sought any constitutional or legislative change.
Ms Harney said yesterday: "I doubt very much if the masters would have come to it looking for changes in legislation, but I know from private discussions with people working in the maternity hospitals in Dublin that there is enormous concern about what is happening."
She said the masters had raised the issues and maintained that something needed to be done.
A social policy that could target those who are completely innocent; William Binchy: page 16