The President of the European Commission will visit Dublin on Thursday and Friday amid serious differences with Britain over the future of the Irish border.
Jean-Claude Juncker will discuss Brexit ahead of this month’s European Council meeting of leaders in Brussels.
This week the EU warned more work was needed on how to deal with the 300-mile border between Northern Ireland and the Republic, the UK’s only land frontier with a European state, and protect frictionless movement after the withdrawal.
Mr Juncker will meet Irish Taoiseach Leo Varadkar, receive an honorary doctorate from the National University of Ireland and attend an official dinner hosted by the Taoiseach in Dublin Castle.
On Friday the Commission President will meet Irish President Michael D Higgins and visit the home of the Gaelic Athletic Association (GAA), Croke Park, and the GAA museum.
He will also watch a demonstration of Gaelic football and hurling.
Rules governing the border post-Brexit represent one of the most vexed issues facing the negotiators in Brussels.
Advances have been made in a number of areas, such as customs, VAT and nuclear waste regulation, EU chief negotiator Michel Barnier has said, but “a lot more work” needs to be done to meet the October deadline.
Mr Juncker will be accompanied by EU agriculture commissioner Phil Hogan and Mr Barnier.
Later this morning Mr Juncker will address the Irish parliament, the Oireachtas.
Mr Varadkar has suggested other countries will baulk at signing trade deals with the UK post-Brexit if Prime Minister Theresa May fails to honour commitments made to the EU on the Irish border issue.
Both sides have agreed to include a so-called “backstop” option in the withdrawal treaty, which would commit the UK to align with an EU regulatory framework in the absence of a wider trade deal.
But the shape of that fallback remains a sticking point, with the EU rejecting a UK contention that it should only be temporary, even if a broader agreement fails to materialise.
Britain’s plan for a temporary customs “backstop” is “not acceptable” and any fall-back option cannot be time-limited, the European Parliament’s chief Brexit co-ordinator has told MPs.
Guy Verhofstadt said the Government’s position that the backstop of continuing UK alignment with the EU customs union would cease by the end of 2021 if no other solution was found left him “puzzled”.
The Taoiseach said: “I’m very much looking forward to President Juncker’s first visit to Ireland as Commission President.
“I will thank President Juncker and Michel Barnier for their ongoing support for Ireland and their show of solidarity throughout the Brexit negotiations.
“This is an important opportunity to assess the state of play in the Brexit negotiations.
“We need to see much more progress from the UK to implement the commitments they made in December and March, and I expect the UK’s efforts to intensify in the period ahead.”
He added: “President Juncker and I are both very committed to the European project and the benefits that it brings to citizens across the Union.
“We will also discuss other key items on the agenda of next week’s meeting of the European Council such as trade, ensuring a stable euro, and equipping the Union with a budget for its future needs.”