The Criminal Assets Bureau is expected to bring corruption charges against the former minister for justice, Mr Ray Burke, arising from payments he received during his political career.
Last week CAB served Mr Burke with a bill for just over €2 million in respect of unpaid taxes on payments he received over the past 25 years.
Mr Burke is expected to appeal the demand, which was delivered in person to his home by CAB officers. He has 30 days in which to do so.
Mr Burke was at home yesterday at Griffith Downs, off the Swords Road, but declined to comment to reporters outside. His home is held in his wife's name and Mr Burke is not believed to own any other property. However, he has an extensive investment portfolio and should be in a position to settle his affairs without having to sell his house.
He has also told the tribunal about a "political fund" of £118,000 which is the remainder of election contributions he says he received during his career.
CAB has been investigating the former minister since September 2002, shortly after the interim report of the Flood tribunal found he received corrupt payments totalling almost €250,000. The acquisition of his former home in Swords was also found to be corrupt.
Bureau officers searched his current house shortly after and took away a large amount of documentation. A number of business premises in Dublin and Meath, including the offices of an accountant and a solicitor, were also searched.
It is understood this criminal investigation is continuing and may result in Mr Burke facing charges similar to those brought against the former Dublin county manager, George Redmond.
Mr Redmond is currently in Cloverhill jail after he was convicted on corruption charges last week. He faces up to seven years in jail when sentenced next month.
The year-long investigation by the bureau identified between €300,000 and €400,000 in income from 1973 to the early 1990s on which it believes Mr Burke did not pay income tax.
The rest of the €2 million-plus sum being demanded from him is made up of penalties and interest in respect of the core amount.
Mr Burke and his advisers are expected to meet CAB officials shortly and may try to negotiate a settlement lower than the amount demanded. He can also pursue the matter in the courts if a settlement is not reached.
However, if he opts to contest the demand, the onus of proving it unfounded will rest with him. In the event of a ruling against him, CAB has the power to seize his assets if he does not have the cash to meet a tax bill. Since being served with the demand last week Mr Burke has not contacted CAB.
Opposition spokesmen yesterday responded to the news by questioning the Taoiseach's description of Mr Burke in 1997 as "an honourable man". Labour's Mr Joe Costello said this description raised questions about Mr Ahern's judgement.
"Mr Ahern has been either extraordinarily unlucky with his political friends or has shown exceptionally poor judgment in those he has chosen as his political associates," Mr Costello said.
The Green Party's Mr Ciarán Cuffe said he hoped the move was an indication that "white-collar crime and political corruption will now be tackled seriously".