Government ministers are holding a special Brexit-related Cabinet meeting.
It is the second time the Cabinet has met to discuss Britain's exit from the EU in 24 hours.
— Josepha Madigan ⚖️✨ (@josephamadigan) March 11, 2019
Some ministers left the meeting to take a break, but are set to return after 10.00pm.
It comes as British Prime Minister Theresa May and European Commission President Jean-Claude Juncker meet in Strasbourg for talks.
Tánaiste Simon Coveney said he understands Mrs May will "try to finalise an agreement... if that's possible" with Mr Juncker.
Speaking earlier, Mr Coveney said: "Negotiations are ongoing. Many had hoped we would have clarity at this stage - particularly in advance of the vote tomorrow. We don't, yet.
"I don't think it's helpful to go into detail of what the obstacles are to getting an agreement - there are some.
He added: "Our approach remains the same: we're very clear that the withdrawal agreement can't change in terms of text, but we also want to try and be helpful in terms of providing the clarity and reassurance needed in Westminister.
"Nobody's looking to trap anybody anywhere permanently - but the backstop needs to be there."
Mrs May and Mr Juncker have already spoken by phone, and talks between the EU and UK negotiating teams are continuing.
Earlier, both EU and British officials confirmed talks were deadlocked.
The British government has been trying to secure concessions from the EU over the backstop to avoid a hard border in Ireland.
However, Downing Street has admitted that negotiations remain at an impasse.
Mrs May and Mr Jucker met at 8.00pm Irish time, according to EU Commission spokesperson Margaritis Schinas.
— Margaritis Schinas (@MargSchinas) March 11, 2019
She then held talks with the President of the European Parliament, Antonio Tajani.
All this also comes ahead of a second 'meaningful vote' in the House of Commons on the Brexit deal on Tuesday.
The first vote was the largest defeat for any government in modern UK parliamentary history.
If it is defeated again, politicians will be asked whether they reject exiting the EU without a deal.
If that is also rejected, MPs will be asked to vote on whether they approve of a short extension to Brexit.
This week's votes come just over two weeks before the UK's due to leave the EU on March 29th.