Government members are concerned that information about a senior political figure, likely to come before the Flood and Moriarty tribunals, could further destabilise the coalition.
Ministers are anxious that matters already before the tribunals and being investigated by Departmental inspectors should be dealt with quickly rather than emerge through press leaks.
A Progressive Democrats spokesman was last night anxious to deny reports of a worsening relationship between the Taoiseach, Mr Ahern, and the Tanaiste, Ms Harney. He said it was "not the case that Fianna Fail and the Progressive Democrats are at breaking strain."
The Taoiseach is currently seeking advice from the Public Offices Commission about the political contributions he himself declared last year. Mr Ahern returned a total of £3,000 for the 1997 general election. But, as reported in yesterday's Sunday Tribune, he made no reference to the O'Donovan Rossa Cumann, which runs an annual £170-a-head dinner to cover the cost of an expensive constituency operation on his behalf in Drumcondra.
A spokesman said Mr Ahern believed he had made a full declaration but, just in case, he was now seeking the advice of the commission. However, it was his belief that expenses incurred by a party for its TDs during an election campaign need not be declared.
Meanwhile, Fianna Fail, Fine Gael and the Labour Party face investigation by the Revenue Commissioners over arranging invoices for donor companies during past general elections, which could be used to disguise their political donations or to reduce their corporation tax liabilities.
Following an internal Rennicks/ Fitzwilton investigation into the £30,000 donation to Mr Ray Burke in 1989, it was discovered that a receipt for the amount was made out by Irish Printers, a company then owned by Mr Paul Kavanagh, Fianna Fail's official fund-raiser, for services provided. This was an example of the "pick-me-up" arrangement now being examined by the Revenue.
The discovery made by Fitzwilton/Rennicks raises questions about the receipt found at Fianna Fail head office last March and sent to the Flood tribunal which records a £10,000 donation from Rennicks, dated two days after Mr Burke received a cheque for £30,000 made out to cash.
The Taoiseach told his parliamentary party on Thursday he had, two weeks previously, advised the Revenue about the existence of the pick-me-up arrangement and had sought a ruling. It is understood he advised the Tanaiste, Ms Harney, about it at about the same time.
A Fianna Fail spokesman said it had brought the practice to the attention of the Revenue and had "handed over some examples". As far as could be established, he said, the practice had not been widespread and would have accounted for about 5 per cent of funds raised at election times.
Fine Gael is also investigating the matter. Any transaction intended to facilitate tax evasion was wrong, a spokesman said, and it was trying to establish if any such wrongdoing had taken place. Any information in that regard would be given to the Revenue or the Garda, but the practice was unlikely to have been extensive.
A Labour spokesman said the record books would be examined and if anything emerged it would be dealt with "in the appropriate fashion." If the practice did exist within the party, it would have been on a very small scale compared to Fianna Fail and Fine Gael, he said, because Labour had not much contact with the corporate world.
The Revenue investigation opens up the possibility that some companies may face tens of thousands of pounds in penalties and back taxes for their involvement in the pick-me-up schemes. Non-manufacturing companies would be liable to 49 per cent tax on their donations, if they were entered as before-tax expenses, while manufacturing companies would be exposed to a 10 per cent charge.
Disclosure of the Fitzwilton/ Rennicks receipt for £30,000 in 1989 also raises questions about who knew what, and when, within Fianna Fail. The Taoiseach told the Dail he only learned about the Rennicks donation last March. But Mr Kavanagh, the party's fund-raiser, is said to have advised the former Fianna Fail treasurer and current TD for Laois-Offaly, Mr Sean Fleming, about the matter in 1989.
This arose after Mr Kavanagh, who knew in advance of the Fitzwilton donation, had failed to extract more than £10,000 of the £30,000 donation from Mr Burke, even though his company had provided a receipt to Fitzwilton/ Rennicks for the full amount of £30,000.