Fianna Fáil TD, Ms Beverly Flynn, has reiterated her claim that the plan to expel her from the party is unfair and does not reflect the treatment received by other errant party members.
The parliamentary whip was removed last night at a meeting where the Taoiseach, Mr Ahern, spoke at length in advocating her expulsion.
Ms Flynn said the move to expel her from the entire party when its national executive meets on Friday was "unprecedented".
"I believe I have been singled out," she told RTE radio this morning.
The last person expelled from the party was Mr Desmond O'Malley in 1985 - he went on to found Fianna Fáil's coalition partner the Progressive Democrats.
A number of other Fianna Fáil TDs have been found to have transgressed since - including several in respect of paying taxes - but while they have had the party whip removed, none have been expelled.
Ms Flynn last week lost her Supreme Court appeal against a ruling that she had encouraged people to avoid paying tax when selling investment products for National Irish Bank (NIB) in the 1980s.
When the High Court made the original finding in a libel case taken by the Mayo TD against RTE, it concluded Ms Flynn had no reputation to defend.
She maintained today that she had worked in accordance to the instructions and policies of the NIB, and at the time she sold the products, did not know she was doing anything wrong.
Her position on this has not changed despite the courts' findings, she said.
"The treatment that I am receiving is different and it's unprecedented [in comparison] to the treatment of any other person who has received the sanction of the Fianna Fáil parliamentary party in the past," she said.
She was regretful about losing the whip and the threat of removal from the party. She was democratically elected by the people of Mayo who would be disenfranchised if the expulsion goes ahead, she maintained.
While Ms Flynn has the backing of her constituency party and a number of members on the 98-member Fianna Fáil national executive, it is expected the two-thirds majority required for her expulsion will be achieved.