The Taoiseach Leo Varadkar has held a phone call with the British Prime Minister Theresa May amid new Brexit uncertainty.
The Department of the Taoiseach said Mrs May sought the call on Monday to update Mr Varadkar on the current state of the negotiations.
It comes after it was reported Mrs May will bring new proposals aimed at avoiding a hard border to her cabinet on Tuesday.
According to reports, she will table a plan which would see the whole of the UK stay in a customs union with the EU - so no checks at the border would be needed.
But the UK want there to be a time limit on any backstop measure.
The Irish Government has ruled that out - and has said the current backstop for Northern Ireland will still have to be part of any final deal.
Responding in a tweet, Tánaiste Simon Coveney Coveney said a "time-limited backstop", or a backstop that could be ended unilaterally by Britain "would never be agreed to" by Ireland or the European Union.
"These ideas are not backstops at all (and) don't deliver on previous UK commitments", he added.
The Irish position remains consistent and v clearâ© that a “time-limited backstop” or a backstop that could be ended by UK unilaterally would never be agreed to by IRE or EU. These ideas are not backstops at all + don’t deliver on previous UK commitments â¦â¦#Brexit pic.twitter.com/y7AQ8V1jMo
— Simon Coveney (@simoncoveney) November 5, 2018
During their phone call, both Mr Varadkar and Mrs May "emphasised their commitment to avoiding a hard border and the need for a legally operable backstop."
Mrs May raised the possibility of a review mechanism for the backstop - to which Mr Varadkar indicated an openness to consider.
But, he said, that was provided that it was clear that the outcome of any such review could "not involve a unilateral decision" to end the backstop.
He also recalled prior commitments made that the backstop must apply 'unless and until' alternative arrangements are agreed.
Both leaders expressed hope that negotiations could conclude in a satisfactory manner as soon as possible.
