Leo Varadkar is attending his first European Council summit as Taoiseach
The Taoiseach Leo Varakdar has said a good Brexit deal for Ireland is more important than a timely one.
He is in Brussels for his first meeting of EU heads of state and government.
Mr Varadkar has met with President of the European Commission Jean-Claude Juncker and EU Brexit negotiator Michel Barnier.
He has also held talks with the EU Council President Donald Tusk.
In all instances, he has relayed Ireland's position in securing a Brexit deal that has the least damaging effects for the Irish economy and political stability.
Asked about the timeline of Brexit negotiations, Mr Varadkar said: "I think what's much more important than the timetable is the outcome.
"I would much rather that we have a good deal for Ireland in time, than one that doesn't work for us in a shorter time period.
"And of course when it comes to issues relating to the border... it'll be difficult to determine the final shape of that until we know what the new trade arrangements are between the United Kingdom and the EU.
"But our objective is a very clear one, and it's a very simple one: that there should not be an economic border between Northern Ireland and the Republic of Ireland".
The British Prime Minister Theresa May is expected to provide the leaders with detail on the status and rights which the UK plans to offer EU citizens living in Britain after Brexit.
It is understood she will explain the UK's "principles" on the issue of citizens' rights - a key early topic in the Brexit negotiations.
She will seek to reassure leaders of her commitment to a fair Brexit deal for both sides by presenting an overview of the UK's intentions regarding the estimated 3.2 million EU citizens currently living in Britain.
Issues such as pensions, healthcare and residency status are all at stake. Even EU nationals married to Britons have been unsure of their status post-Brexit.
In turn, British citizens in the EU have been offered no details or assurances on their future.
Mrs May is not expected to detail any of the specifics of how citizens rights will be protected, but instead give broad assurances.
The two-day Brussels summit will predominately focus on counter-terrorism, common defence and security.
Two foiled terrorist attacks this week alone put renewed focus on EU-wide efforts to improve counter-terrorism measures.
In Paris on Monday, a man was apprehended after he tried to ram his car into police on the Champs Elysee and in Brussels on Tuesday, a man attempted to detonate a nail bomb in the city's Central Station. No one was injured in either incident.
Additional reporting: Shona Murray & Jack Quann