Independent TD Stephen Donnelly has been criticised by other members of the banking inquiry committee for his decision to resign in protest at the Government's "cavalier" handling of the issue.

There were scenes of uproar in the Seanad last week when the Government added two more members onto the Oireachtas Joint Committee of Inquiry into the Banking Crisis and re-established its majority.

In a unilateral move, the Seanad Leader Maurice Cummins tabled a motion that proposed that two additional Seanad members - Michael D'Arcy of Fine Gael and Susan O'Keeffe of Labour- be added to the committee.

Taoiseach Enda Kenny said on Friday the long-awaited investigation into the banking failure is about searching for the truth, not about “inter-party rows and personalities”.

Speaking in Guernsey, he defended the decision to add two extra Government Senators.

Mr Donnelly today accused the Taoiseach of “treating democracy in a cavalier manner”.

He accepted there was a Government majority on every Oireachtas committee, including the finance committee, of which he is a member.

"That's not a problem, that reflects the will of the people in the last election," the Wicklow TD told RTÉ Radio this morning.

“But when the Taoiseach overrides the will of the Oireachtas and subverts the democratic process, and then explicitly states he is doing so in order to control the banking inquiry, my decision taken last Friday was to say ‘no, I cannot be a part of this. I’m going to stand up and say I’m sorry, I don’t believe this is how politics should be done.’”

Mr Donnelly said Mr Kenny has "completely undermined" the inquiry and its "excellent" chairman, Labour TD Ciaran Lynch.

“Ciaran chairing the banking inquiry is one of the reasons I thought it had hope of being independent,” he said. “But unfortunately, the Taoiseach’s will trumps his will.”

On the same programme, Minister for Transport defended the Taoiseach and said the inquiry will go ahead. He said he was disappointed Mr Donnelly had chosen to resign, and agreed the inquiry would be “poorer” without him. “He’s exactly the type of person who should be on the inquiry, to be there to ask the hard questions and unpick what went on.”

Mr Donnelly’s decision was also criticised by former Fine Gael leader and Anglo Irish Bank chairman Alan Dukes, who accused him of being “a bit precious”.

“He agreed to go on this committee originally where the Government was intended to have a majority and that basically hasn’t changed,” he said on RTÉ Radio’s The Week in Politics.

Speaking on the same programme, Fine Gael TD Kieran O’Donnell, also a member of the committee, rejected Mr Donnelly’s assertions that it would be incapable of impartial inquiry. “I’m very disappointed that Stephen Donnelly has chosen not to be a part of the banking inquiry... He’s prejudging and pre-empting the outcome of this inquiry before we’ve ever met, and I think he’s basing this on a false assumption that members like myself will not be impartial,” he said.

Public Accounts Committee member and Independent TD Shane Ross suggested the banking crisis should be assessed by external sources rather than members of the Oireachtas.

“They’ve been selected because of their party political loyalties and they will not be leaving party politics at the door,” said Mr Ross. “I’ve researched members of this inquiry already and I’ve found that they’ve all said things that are highly prejudicial to what they’re doing now.

“There is a very good case for taking people who are external to the country and who aren’t involved in the extraordinarily incestuous financial world who would make a less partial judgement,” he added.

In a statement this afternoon, Fianna Fáil finance spokesman Michael McGrath said the banking inquiry is a "mess" and called on the Government to revisit its decision to reject an independent Leveson-type investigation.

“This latest development, with the departure of a well qualified and respected independent TD plunges the process into even further trouble,” said Mr McGrath. “The Government must change the approach it has adopted over recent weeks and realise the scale of the problem it has created. The entire viability of the inquiry, whether Fine Gael and the Labour Party like it or not, is in jeopardy.

He said Fianna Fáil has “made it clear repeatedly” that it will fully engage in whatever process is in place.

Earlier this month, the Seanad selection committee for the banking inquiry chose two non-Government members of the Upper House to sit on the all-party inquiry.

Three Government senators were absent from the meeting, including its nominee Senator O’Keeffe. Fianna Fáil’s Marc MacSharry was instead selected. Ms O’Keeffe said she had arranged as far back as last autumn for a pair, so she could be in Sligo giving her daughter support in her Leaving Certificate exams. She had not seen the email notifying senators about the meeting.

In a development that caused major embarrassment to the Government, it found itself with minority representation on the committee.

The Taoiseach told the Dáil last week the Government needed a majority on the committee in order to set its terms of reference.