Tánaiste Simon Coveney has warned British politicians opposed to the Brexit withdrawal deal that the "time for wishful thinking is over".
Minister Coveney was speaking at the Global Ireland Heads of Mission Conference at Dublin Castle, with German foreign minister Heiko Maas also in attendance today.
The gathering comes as British Prime Minister Theresa May continues her bid to win support in Westminster for the withdrawal deal ahead of the planned 'meaningful vote' in the House of Commons next week.
She is also continuing to seek "further undertakings" from the EU in her bid to win over sceptical MPs, many of whom have voiced opposition to the 'backstop' to avoid a hard border in Ireland.
However, the European Commission has repeatedly warned that there will be "no negotiation" on the terms of the deal agreed by all 28 member states last year.
A report in the Daily Telegraph today also claims that British and European officials are "discussing the possibility of extending Article 50" beyond the planned exit date of March in order to avoid a no-deal situation.
That has been strongly denied by Downing Street.
"Fateful days"

German minister for foreign affairs Heiko Maas (right) and Tanaiste Simon Coveney at Dublin Castle today. Picture by: Niall Carson/PA Wire/PA Images
Speaking in Dublin today, Simon Coveney said these are "fateful days and weeks" in British politics.
He said he remains convinced that MPs will do all they can to avert a "disastrous crash-out Brexit".
He also firmly defended the withdrawal deal, describing it as "fundamentally a good one".
The Tánaiste observed: "One thing is certain – the time for wishful thinking is over. There is no alternative 585-page agreement waiting to be dusted off.
"And it is also wishful thinking to ignore the default outcome if nothing else is agreed – that default is a crash-out. Surely now is the time in Westminster for everyone, in government and in opposition, to cast aside unrealistic options based on promises that simply cannot be delivered."
He added: "If that doesn’t happen quickly, in the absence of that realism, it is the hardliners who think no price is too high to pay for their version of Brexit who will win out to everyone’s cost, including Ireland’s."
Meanwhile, Minister Coveney also said Ireland wouldn't stand in the way if the UK wants to delay Brexit by extending Article 50.
Speaking during a press conference with Mr Maas, Minister Coveney observed: "If it is the case that at some point in the future... that the British government seeks an extension of Article 50, that's obviously something that will have to get consideration at an EU level.
"Certainly from an Irish perspective, if such an ask happens and is justified, we won't be standing in the way of that."