The Government says it wants agreement on all the withdrawal issues by the time of the October EU summit, however there are severe doubts that that can be achieved.
"We have Ireland backed by 26 member states and the commission - this will not change".
While welcoming the joint statement from the European Commission and the United Kingdom - outlining progress made on the terms of the draft withdrawal agreement since the last negotiation round in March - Mairead McGuinness, the First Vice-President of the European Parliament, framed her views ahead of Brexit meetings in Dublin tomorrow.
"We have advanced on some separation issues for which European businesses need certainty, such as customs, VAT, Euratom and certificates for goods", Barnier said in a statement accompanying a joint declaration from Brussels and London.
"I am strongly against any temptation to try to isolate Ireland".
This week the EU warned that 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.
The Government says it will and Labour is also committed to taking Britain out of the European Union, despite significant unrest on the back benches.
The meetings took place ahead of a European Council summit next week, while Juncker will also address a joint sitting of the Oireachtas.
Ireland's Taoiseach, Leo Varadkar greets the President of the European Council, Jean-Claude Juncker as he arrives at Government buildings in Dublin, Ireland June 21, 2018.
"The Withdrawal Agreement without a backstop is of no use to us whatsoever".
Another paragraph clearly states the temporary customs arrangement will be "time-limited" and will come into force after the Brexit transition period ends in December 2020.
"The aim should be a "Norway plus" model on the basis that the red lines set out by the Prime Minister in her Lancaster House speech in January 2017 are not consistent with the national interest".
A time-limited "backstop" option agreed in principle but not in detail between Britain and the European Union has been interpreted by Europe as meaning Northern Ireland would effectively stay within the bloc's regulatory rules on issues like customs to preserve the now invisible and frictionless border arrangements.
"The greatest challenge we face on this island is to unwrap the enigma, and solve the riddle of Brexit".
Advances have been made in a number of areas, such as customs, Value-Added Tax and nuclear waste regulation, European Union chief negotiator Michel Barnier has said, but "a lot more work" needs to be done to meet the October deadline.
Tomorrow he will meet Irish President Michael D Higgins and visit the home of the Gaelic Athletic Association (GAA), Croke Park, and the GAA museum.
Jean Claude Juncker and Taoiseach Leo Varadkar.