Taoiseach (Irish prime minister) Leo Varadkar has said he still believes a no-deal Brexit can be avoided.
The EU has said there is currently no basis for “meaningful discussions” and talks are back where they were three years ago.
Mr Varadkar is in Northern Ireland on Tuesday meeting business leaders to discuss Brexit.
He was greeted at Hillsborough Castle by DUP MP Sir Jeffrey Donaldson, and business and tourism officials.
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Mr Varadkar was asked if he accepted a no-deal Brexit was now the likely outcome, given the stalling of talks since the new UK prime minister had taken office.
Number 10 has rejected claims it is unwilling to negotiate with the EU and wants talks to fail to allow a no-deal Brexit.
Speaking during a press conference at Hillsborough Castle, Mr Varadkar said a no-deal outcome could still either be avoided, either by ratifying the current withdrawal agreement, agreeing a further extension to the deadline, or revoking Article 50, the mechanism that triggered the Brexit process.
However, Boris Johnson has ruled out any of those options.
The taoiseach also said he understood some people had become “weary” of Brexit and that he believed the UK should leave the EU by 31 October “come what may”.
But he added that even if a no-deal outcome happens, negotiations would need to begin at some stage anyway to try to resolve the Irish border issue.
“Brexit is not a storm we weather or prepare for, it is a permanent change and that needs to be borne in mind,” he said.