EU pushing for North to stay in customs union
The EU is now pushing hard for Northern Ireland to remain in the single market and customs union, separate to Britain, after Brexit.
The move would mean Border checks not having to be put in place.
EU chief Brexit negotiator Michel Barnier has warned Britain's decision to leave the EU single market and customs union will mean checks at the Irish Border are "unavoidable".
After demanding that any solution on the issue be "precise, clear and unambiguous", Mr Barnier is proposing Northern Ireland would stay in the single market and customs union.
He wants the December agreement on no return of the Border written into law, which would force the British side to concede.
The move to treat Northern Ireland differently would be resisted by the DUP. However, the British government would have to push it through.
The outcome would be of benefit to Ireland, and the remainder of the EU countries support what Mr Barnier is proposing.
Meanwhile, a deal to restore devolved government to Northern Ireland is imminent.
British Prime Minister Theresa May will arrive in Belfast today to sign off on an agreement.
Taoiseach Leo Varadkar will also travel to Belfast for talks with Mrs May to assess the state of play in the negotiations to restore the Northern Ireland Executive and Assembly and for engagments with the political parties in the North.
Talks between the two parties were suspended over the weekend as Sinn Fein members met in Dublin to endorse Mary Lou McDonald as their new president. However, bilateral discussions will resume today.
A Downing Street spokesman said Mrs May would take part in a series of meetings at Stormont House and encouraged Sinn Féin and the DUP to resolve their differences.
A spokesman for Mr Varadkar said he and Mrs May would assess the state of play in the negotiations between the two parties.
There is speculation the Government may offer Northern Ireland additional funding if the DUP and Sinn Fein finalise a deal.
Downing Street said Mrs May would tell the parties that her government was ready to introduce legislation to enable the re-establishment of the Stormont institutions as soon as possible if an agreement was sealed.
Mrs May is also due to meet a major employer in Northern Ireland to discuss the British government's commitment to the country.
Meanwhile, the Taoiseach called for clarity from the UK in its approach to Brexit. He said he understood Mr Barnier's frustrations with the British.
"The difficulty is, what we are trying to do with the EU is to ensure what was agreed in December is stitched into the legal text of a withdrawal agreement and the transition period, which the UK is keen to have, is conditional on that," Mr Varadkar said.
"I understand Mr Barnier's frustrations with the lack of progress since December.
"We need clarity from the UK, the last resort still applies."
He also denied that the Brexit deal struck late last year had been oversold.
Labour Party leader Brendan Howlin described his comments as "blasé".
"The Taoiseach has been reduced to seeking clarity on matters he has already declared clear.
"Having been told we had secured a cast-iron guarantee - the Taoiseach's own words - in December, he is now telling us he is still looking for clarity from the British. These two positions are incompatible."