Update 1.35pm: The Tánaiste says the Government is not planning for the return of a hard border.
It is the one scenario Ministers refuse to make a plan for, insisting it will not happen.
The cabinet is meeting at Derrynane House in Co Kerry this afternoon to discuss contingency plans for Brexit.
Tánaiste and Foreign Affairs Minister Simon Coveney says their preparations will not include plans for a hard border with the north.
He said: "What has already been agreed on the Irish border is that Britain has ruled out border infrastructure on the Island of Ireland. We have insisted on that also and EU side has also insisted on it and as far as we are concerned from a preparedness point of view, we are not preparing for something that is not going to happen."
Elsewhere, both Fine Gael and Fianna Fáil have criticised Sinn Féin MPs for not taking up their seats in Westminster.
The parties say those votes could be crucial in the final votes for Brexit.
But Sinn Féin Brexit spokesman David Cullinane has defended their policy.
- Digital Desk
Earlier: Ireland should not 'panic buy' a bad Brexit deal, says Coveney
Ireland and the EU must not become "distracted" by the Westminster Brexit crisis and "panic buy" a Brexit deal that could damage this country due to the ongoing "confusion" in London.
Tánaiste Simon Coveney said this morning the need for calm heads is vital despite admitting the Government is now preparing for all eventualities - including a "very unlikely" hard Brexit.
Speaking to reporters in Derrynane, south west Kerry, before a special cabinet meeting set to be dominated by the Brexit crisis, Mr Coveney said it is becoming "frustrating" to deal with British officials whose position keeps changing.
However, despite the turmoil in Westminster in recent days, the Tánaiste insisted Ireland and the EU must continue to focus on the previous commitments given by Britain and should ignore any rush to "panic buy" a bad deal.
"That is the basis now of the negotiating approach of the British government, and a form of negotiations between the EU and UK.
"What is continuing in Westminster is a dispute within the Conservative party and British politics generally around the kind of Brexit they're advocating for, so people are looking to undermine each other's positions, and I don't think that's a good thing.
"All we're seeing at the moment I think is the use of the legislative process in Westminster to make political points from different factions within the Conservative party and the British system generally, and I think it would be very foolish to over-react to that or to in any way panic buy it or because of it.
"Certainly the Irish Government aren't going to be distracted from that and taken down avenues to commitments which may or may not be relevant in the medium term," Mr Coveney said.
Mr Coveney said despite the ongoing turmoil in Westminster he believes it remains "very, very unlikely" a hard Brexit will ultimately occur because of the number of MPs in Britain who are opposed to such an outcome.
However, he admitted it is "frustrating" to try and negotiate with British officials who are continually changing their position on key matters due to the moving political ground in the UK.
"For example, when there is a new settled position published in a white paper there is then a parliament majority to support potential changes to that.
"But in many ways anyone who's been following the politics of Brexit in Britain will understand just how divisive it is, and when you look at the number of resignations of senior and junior ministers in the UK, you realise just how much of a struggle it is for the British political system to deal with the complexity of this issue.
"And that is why it's so important for Ireland and the task-force to be firm, to be clear, to be consistent in terms of what we're looking for and to also insist on what's already been agreed to be followed through," he said.
Asked if Ireland is preparing for a hard Brexit, Mr Coveney insisted he still believes the outcome is "very, very unlikely".
However, he later confirmed the cabinet is preparing for "all eventualities" as part of a series of contingency plans due to be discussed today.
"We're taking what is called a middle case scenario, in other words the most likely outcomes as we see it today.
"People do need to be reassured that while we've not been talking about contingency planning to date with good reason in the context of negotiating strategy, there has been an enormous amount of work going on for the best part of a year now across multiple government departments and agencies to make sure we are prepared for whatever outcome emerges from Brexit," he said.