Taoiseach Micheál Martin has spoken with a number of Opposition leaders ahead of tomorrow's vote on Dáil speaking slots for Regional Independent TDs and coalition backbenchers.
A spokesperson for Sinn Féin leader Mary Lou McDonald described the phone call as forthright and direct.
"She expressed her disappointment and indeed widely held anger at the behaviour of the Government.
"It is clear that they have absolutely no interest in resolving this issue in an agreed way, and it is questionable whether they ever had any intention of doing so," they said.
Labour leader Ivana Bacik also spoke with the Taoiseach on the phone.
They had a conversation about the vote, and why Labour would not be accepting the Government proposal.
Ms Bacik emphasised once again the need for a meeting with all Opposition leaders in advance of the vote.
Earlier, the Dáil's combined Opposition vowed that it will resist changes to the rules of the house that would grant new speaking time to the Regional Independent TDs.
The Government intends to hold a vote tomorrow to allocate a new question and answer slot to the Regional Independents and coalition backbenchers.
The Opposition is furious and has been weighing up how best to respond.
It seems likely that there will be a sustained protest in the Dáil chamber tomorrow that could once again halt the day's business.
However, the Government's majority ensures it will win the vote.
That would mean the group effectively led by Michael Lowry along with backbenchers would be eligible to pose questions to the Taoiseach on Wednesdays and the Tánaiste on Thursdays.
Speaking after a meeting of Opposition party leaders, Ms McDonald said the Opposition "will not accept it".
In a post on X, Ms McDonald said: "Fianna Fáil and Fine Gael have broken their word. We will not accept it.
"Michael Lowry group are Government TDs. You can't be in Government and Opposition at the same time. Sin é."
People Before Profit's Richard Boyd Barrett said they would not let the Government railroad the change through tomorrow.
"We are not going to make it easy for them, but at the moment, we're waiting to see, will the Government pull back from the brink on this? We don't want to have to disrupt the Dáil, but we're not going to take this lying down," he said.
All you need to know about the Dáil speaking rights row
Earlier, the Minister for Education said it would be an affront to democracy if the Opposition parties stage a walkout ahead of the contentious Dáil vote tomorrow.
Minister Helen McEntee insisted that under the Government's proposal "not a single second of time" will be taken from the Opposition's speaking time.
Speaking on RTÉ's Today with Claire Byrne programme, Minister McEntee said the Government is attempting to ensure that Government backbenchers have a chance to raise questions and issues.
"We're not removing a single second from Opposition, even though that's what they would have everyone believe," she said.
"We are making sure that there is fairness across the board and if you are somebody that has been elected, if you're in Government or you're in Opposition, you will have an ability to raise a question, to raise a concern that your constituents have elected you to do so," the minister added.
The Opposition contends the Government has not meaningfully listened to their concerns since this row dramatically delayed the nomination of Micheál Martin as Taoiseach in January.
Sinn Féin Chief Whip Pádraig Mac Lochlainn said Opposition parties remain united on the issue and they have ruled nothing out in terms of a response should tomorrow's vote proceed.
Speaking on RTÉ's Drivetime, he said the Dáil cannot function without the cooperation of the opposition.
"I don't know any TD who can remember any time where the entire opposition united to defend what we see as our rights in a democracy to hold the Government to account," he said.
The Donegal TD also described Ms McEntee's comments as "disingenuous".
Social Democrats deputy leader Cian O'Callaghan described the Government's plan as divisive.
He said that given the challenges facing the country, the move would create acrimony and is deeply unhelpful.
Mr O'Callaghan urged the Government to reconsider the proposal as he believes the current approach is counterproductive.
