It is "likely" EU leaders will give the green light for Brexit talks to focus on trade, at their meeting next month, the Irish prime minister has said.
Leo Varadkar said this was his own belief rather than a forecast of any European Council decision.
He said it would not be possible to settle the question of the border with Northern Ireland until the shape of the future EU-UK relationship emerges.
He was speaking in the Dáil (Irish parliament).
It is the first time Mr Varadkar has expressed the view that the Brexit talks could proceed to the phase focussed on trade, as well as a transition period after Britain leaves the European Union in March 2019.
Previously, the EU has said talks on trade can only happen when the European Council decides there has been "sufficient progress" on three issues: the so-called divorce bill when the UK leaves, the rights for EU citizens in the UK and UK citizens in the EU and the Northern Ireland border.
The taoiseach (prime minister) said it was a "rapidly changing situation" and that he had given his views on the state of play in the talks ahead of the European Council meeting last month.
"When we were at this point back in September/October, I indicated that I didn't think it was likely that we could say that sufficient progress has been made," he added.
"I am now of the view that I think it is likely that we will be able to say that sufficient progress has been made at the December meeting, allowing us to move on to discussions on transition and the future arrangements, but that is just my predictor at this stage.
"This of course will all depend on what happens over the next number of weeks, what specific assurance and guarantees we can get in writing from the United Kingdom.
"I can't predict the future, I don't know what is going to happen in the next couple of weeks or couple of months but it is my sense that we are moving in the right direction and I am more optimistic than I was in the weeks before the October summit. However, that may change."
Earlier this week, the Northern Ireland secretary of state said it was "difficult to imagine" Northern Ireland remaining in the EU's single market and customs union after Brexit.
James Brokenshire was in Brussels updating leading EU figures on Stormont's current political situation
He was also discussing Brexit issues affecting Northern Ireland as the UK prepares to leave the EU.
Mr Brokenshire was speaking after a meeting with the EU's chief Brexit negotiator, Michel Barnier.
In a speech he repeated the government's commitment to protect the Good Friday Agreement, the Common Travel Area and the UK's own single market.