Plans to permit members of the Stormont Assembly to participate in Dáil debates are the product of "a misguided and foolish Irish establishment", according to the Ulster Unionists.
Mr Michael McGimpsey, a former minister before the Stormont institutions were suspended, said the idea was a sop to Sinn Féin, adding it was "a fig leaf for them buying into British Ulster".
Mr McGimpsey said: "Picture the scene in Leinster House with republicans of varying shades of green vying to out-do each other in a scene more reminiscent of a Monty Python sketch. On one side, those who claim to be the genuine republican variety in Bertie Ahern's Fianna Fáil Party, while opposite them, the Marxist-Leninists of Sinn Féin backed by a private army."
He questioned Mr Ahern's position statement before the last general election in which he would not consider Sinn Féin as a coalition partner because of the continued existence of the IRA.
"It appears it is acceptable to have Sinn Féin in the downstairs kitchen for a bit of old-fashioned window dressing, but it is not all right to have them sitting in the dining room."
Mr McGimpsey said Leinster House needs to recognise that its writ ends at the Border and that there is no mandate for any Assembly member to participate in debates outside Stormont.
"What has the electorate of the Republic of Ireland done to deserve this? Now they are being told that a parcel of politicians without a mandate, or no political or moral authority to sit in the Dáil, will now have a direct say in how the country is run. This is not democracy and by definition, the absence of democracy is a form of tyranny. It is a farce."