The Revenue Commissioners are understood to have only two names of those with money in the controversial National Irish Bank (NIB) deposits scheme.
But Democratic Left TD Mr Pat Rabbitte has said he will supply the list of depositors in his possession to the Commissioners.
"I would have no difficulty at all doing that in due course," he said. "But my understanding was the names had already been supplied to the Revenue."
Mr Rabbitte is also maintaining his call for the Tanaiste, Ms Harney, to appoint an inspector, with whom he would co-operate, to investigate the bank.
"It is difficult to understand the reluctance of the Tanaiste to have an inspector appointed to investigate certain matters in respect of National Irish Bank," he said.
He added that Ms Harney had a duty to put in an inspector, whose report would ultimately come into the public domain.
A spokesman for the Tanaiste said Mr Rabbitte had a moral duty and a duty as a legislator to hand over the list to the Revenue Commissioners, especially if he was satisfied that it was a list of genuine tax defaulters.
But he added that strong evidence of illegality would be needed to sustain a case for the appointment of an inspector by the High Court.
The Revenue has been investigating National Irish Bank since the controversy broke several weeks ago. However, under current legislation, the Revenue has no right to trawl bank records for depositors' names. It is understood it has been using its time in the bank to conduct a very detailed investigation into the workings of the scheme and how it was marketed.
So far, it is believed that the Revenue has been provided with only two names out of the suspected 180 depositors who invested £180 million in the controversial Clerical Medical bonds.
It is not clear how many names Mr Rabbitte has in his possession, but it is understood it is only a portion of the total.
Most of the depositors were involved in businesses with large cash elements. A garage owner, a hotelier, others in the tourist industry and farmers are among those who invested in the offshore bonds. Two county councillors are also said to be account holders.
Mr Derek McDowell, Labour finance spokesman, has called for National Australia Bank, NIB's parent, to publish the results of its own internal investigations and for the Dail Select Committee on Fiance and General Affairs to investigate banking supervision and regulation.
NIB is understood to have targeted potential users of the scheme and encouraged them to buy investment bonds in the Isle of Man investment company Clerical Medical. The bank then advised the customer to have the investment returned as a deposit with NIB.
The returns on this scheme would not have been exceptionally large but it would be an effective way for the customers involved to evade tax.
