Irish Prime Minister Leo Varadkar has ruled out formal three-way talks between the UK, Ireland and the EU to look at the Theresa May's Brexit offer.
Mr Varadkar said it was not in Ireland's interests to take part in such talks regarding the withdrawal of the UK from the EU, and that what was needed was for Downing Street to produce more detailed proposals.
The comments came after the Prime Minister on Sunday suggested Mr Varadkar had agreed to form three-way talks to look at the Irish border element of the proposals she outlined on Friday.
Mrs May set out her strategy for negotiations on the UK's future relationship with the EU in a high-profile speech in London.
It will be put to the test this week as negotiations between British and European Union officials resume in Brussels.
The Irish PM said: "There won't be tripartite or three-way talks.
"What will happen is that there will be talks between the EU 27 and the UK, and Ireland is part of the EU 27 and we're much stronger by the way as one of 27."
Mr Varadkar added consultations could take place between the two governments about issues that are unique to Ireland.
"We will of course have negotiations about what could be done to avoid a hard border, but what we won't be getting into is a negotiation with the UK, or a three-way negotiation," Mr Varadkar said.
"That's not in our interest and not the way that this can be concluded."
The Taoiseach told RTE's Morning Ireland programme that he gave Mrs May's Brexit speech on Friday a guarded welcome, but that detail was now needed from the UK Government.
"What we want is not so much principles and aspirations and red lines," Mr Varadkar said.
"What we want is detail, written down in black and white that can be codified into law and that is what is required."
Mrs May's speech earned her breathing space from warring Remain and Leave factions in the Conservative Party, but her plans for maintaining a soft Irish border while leaving the customs union were thrown into doubt when Irish Tanaiste and foreign minister Simon Coveney said the EU may not accept her proposals.
The technical negotiations in Brussels from Monday to Wednesday will focus on the issue alongside a proposed transition period and other withdrawal issues including the financial settlement and citizens' rights, on which disagreements still need to be ironed out.
Mrs May is hoping to get a post-Brexit transition period signed off at the European Council summit of EU leaders on March 22-23, clearing the way for exploratory talks on trade.
But tensions over the Irish border issue remain and could hold up agreement.
Amid the ongoing row over the border, Sinn Fein leaders Mary Lou McDonald and Michelle O'Neill travelled to Brussels on Monday to meet EU chief negotiator Michel Barnier.
Mrs May has rejected Brussels proposals that would see Northern Ireland kept in an effective customs union with the EU as a fallback in case other solutions cannot be found.
She has proposed technological solutions and an exemption from new restrictions on the 80% of cross-frontier trade carried out by smaller businesses.
But on Sunday, Mr Coveney told BBC One's The Andrew Marr Show he was "not sure that the European Union will be able to support" the plan, as it would be worried about protecting the integrity of the single market.
Mrs May's de facto deputy, Cabinet Office minister David Lidington, said her speech was an "ambitious opening bid" and suggested the border proposals could be tweaked.