Update 5pm: The Foreign Affairs Minister says Ireland is firmly on Team EU and will not be a proxy for the UK in Brexit talks.
British Prime Minister Theresa May's formally triggered 'Article 50' and divorce proceedings with the EU will now begin.
They are expected to take at least two years with Britain saying it still wants a new deep and special partnership with the EU - from the outside.
The official letter starting the process made specialmention of the Republic of Ireland, the peace process and a wish for no hard border.
But Minister Charlie Flanagan has said Ireland's position on negotiations is now with the other 26 EU countries.
Earlier: Negotiating Brexit will "be very challenging and very complicated" Taoiseach Enda Kenny has said, writes Elaine Loughlin.
Reacting to the triggering of Article 50 by the British Government, Mr Kenny has remained adamant that Brexit will not signal a return to a hard border on the island of Ireland.
Mr Kenny welcomed the fact that Theresa May had made reference to the importance of protecting both Northern Ireland and Ireland in her letter but he added that "a country can't be seen to be advantaged by leaving" so negotiations would have to take account of that.
Speaking at the EPP congress in Malta this afternoon Mr Kenny said: "The trading positions, relationships between the United Kingdom and the European Union are critical issues, I think these will run a lot longer than the two year period but central to that will be no return to a hard border as the only land border in the union.
"It's now a reality that we have to deal with the consequences of the vote of the United Kingdom
"This will not be easy, it will be very challenging and very complicated, we have set out our priorities and our main objectives."
Outlining the priorities of protecting the peace process, the Good Friday Agreement and the open border on the island of Ireland he said he was "glad to see that these are reflected in the letter of the British Prime Minister to the President of the European Council".
He added that both the British and Irish governmetn had agreed that "there should not be and will not be a return to a hard border and by that I mean customs posts on the road from Dundalk to Derry that brought with it sectarian violence over a long period and brought about all those troubles."