Independent Deputy Stephen Donnelly is calling for the Oireachtas banking inquiry to be carried out by an independent body - with no politicians - after he announced that he is to withdraw from the inquiry.
The Wicklow Deputy made the comments following his resignation from the Inquiry, after the coalition this week added two senators to the committee to ensure it had a Government majority.
He says the actions of the Government have shown that they will use their majority to control the outcome of this investigation and that the original "unintended composition" of the committee would have been trusted by the public far more than one with a Government majority.
"I think what we're seeing at the moment is politics at its worst," he said.
"We have an executive and a Taoiseach who clearly has no regard for due process within the Oireachtas and is willing to overturn that.
"And you kind of have to ask yourself: 'If the Taoiseach is willing to overturn due process in the Oireachtas to enforce his will when he didn't get his way, well, what else is up for grabs?'."
Fianna Fáil's Finance spokesperson is also calling on the Government to make the Banking Inquiry an independent Leveson-type inquiry.
Michael McGrath says the Government's move last week completely undermines the entire process and the Coalition must now change its approach.
However, he said at this stage he has no plans to resign from the committee.
"Well, Fianna Fáil is going to fully participate with whatever inquiry takes place," he said.
"We have a democratic duty to do so, and we, more than anybody, want to see this inquiry conducted in a fair and impartial manner, and to give a proper assessment of what led to the banking crisis and to have a fair analysis of how that crisis was handled.
"So we are going to participate."