Leo Varadkar says more concessions are needed
EU leaders have welcomed British Prime Minister Theresa May's latest offer to free up Brexit negotiations.
However they talked down chances of them moving on to the crucial trade stage.
German Chancellor Angela Merkel arrived at a summit of the 28 countries in Brussels, praising the "encouraging" progress.
Mrs May trailed her journey there with news she would make it easier for the three million EU citizens living in Britain to remain here after March 2019.
But EU leaders are expected to vote down a motion confirming "sufficient progress" has been made since Article 50 was triggered.
That would mean Britain's Brexit Secretary David Davis is powerless to begin negotiations on the UK's future relationship with the EU - including on trade.
Mr Davis gave an interview on the eve of the summit trying to exert his own leverage, calling for the EU's chief Brexit negotiator Michel Barnier to be given "more leeway in his mandate".
But French President Emmanuel Macron downplayed the idea, telling reporters as he arrived in Brussels that the EU27 was "united" behind Mr Barnier.
Taoiseach Leo Varadkar has said that "further concessions" will be required from the UK government.
The Maltese Prime Minister, Joseph Muscat, also went on the defensive.
He said it was "pretty clear" EU leaders would vote down the "sufficient progress" motion.
He did say a statement would be passed in the "spirit" of progress and added: "The wording will be encouraging."
Mrs May remained defiant at the summit, hailing the "concrete progress made so far" and stressing "urgency" of agreeing deals on things like citizens' rights.
She added the UK would play a full role in dealing with the shared challenges of counter-terrorism, migration and defence.
The EU27 will consider whether Brexit talks have achieved "sufficient progress" on key divorce issues, their condition for allowing trade talks to begin, after Mrs May has left the summit on Friday.