Taoiseach Leo Varadkar has insisted negotiations on Britain's split from Europe are not on a cliff edge to a hard Brexit.
On arrival at the European summit in Brussels, the Taoiseach urged Britain to bring forward more detail on solutions to the Irish border questions and customs relations.
With German Chancellor Angela Merkel saying there encouraging signs that talks on future UK/EU trade relations could begin as early as December, Mr Varadkar also said he was optimistic of more common ground in the Brexit talks by next month.
Mr Varadkar also said progress has been made on the Irish border, "just not enough".
He had a similar message on the question of customs, adding that suggestions of a customs partnership between the UK and the EU, rather than a customs union, needs to be teased out.
"I find it difficult to square the circle of having a customs partnership which is very like the customs union we have now but at the same time Britain engaging in trade deals with third parties," he said.
"A customs union is a little like a marriage - once you are committed to it, you are committed to it."
The Taoiseach said Brexit negotiator Michel Barnier's assessment of the talks should focus minds in the run up to December and amid mounting pressure for movement on the trade issue.
But he distanced himself from remarks by Ireland's EU Commissioner Phil Hogan who said the negotiations on the UK's split from Europe are on a cliff edge to a hard Brexit.
"I think we have a way to go yet," he said.
"Brexit does not happen until April 2019. We are quite far back from the cliff edge at this stage.
"But it's incumbent on the EU prime ministers and presidents to ensure that we don't sleepwalk towards that cliff and that substantially more progress is made in the next couple of months.
"We are well away from the cliff."
Mr Varadkar also called for a lot more detail from the UK on how the Irish border will remain open after April 2019.
"Language isn't enough," he said.
"If the UK is leaving the European Union it is on them to put forward detailed proposals to ensure that things remain much the same. That is at the core of the conflict with the position that the UK is taking."
