The Minister for Foreign Affairs has admitted a hard border between Northern Ireland and the Republic cannot be ruled out as part of the Brexit process.
Charlie Flanagan said he has discussed the issue with UK ministers and believes they have an understanding that they do not want a return to the border of the past.
British Prime Minister Theresa May has confirmed she will trigger Article 50 by the end of March next year, and hopes to have left the EU two years later.
Minister Flanagan said: "That scenario (of a hard border) cannot be ruled out.
"(However,) I have been speaking to all of my 26 EU colleagues over the past few weeks, and I have impressed on them that we cannot go back to the old days of a heavily fortified border between us, because over 30,000 people cross every day."