Tánaiste Simon Coveney has called on the British government to drop its red lines and tough talk on its future relationship with the EU.
He said a calm and rational debate on the merits of continued membership of extended customs union and single market structures was overdue.
Addressing a conference bringing together concerned business representatives on both sides of the border, the Minister for Foreign Affairs warned that the clock was ticking on a decision on what future trading relations will look like after Brexit.
He told the event in Co Louth that the best interests of the UK, Ireland and the wider EU would be served by an arrangement as close as possible to the current free-flowing status quo.
"In our view this is best accomplished by the UK indicating that it wishes to be part of an extended single market and customs unions, allowing it to continue to access the world's largest and most successful free market - a market British genius has helped design," he said.
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"Thus far however, as we know, the British government has not been prepared to seek that type of relationship.
"My hope is that in the coming weeks, previous red lines and tough talking points will be put to one side and a calm and rational debate about what is in the best interests of the people of Britain and Northern Ireland can prevail.
"That deliberation is overdue.
"And the clock is now ticking closer to the time when a decision on the future direction is needed.
"The closest possible customs and regulatory partnership is in the best interests of everybody, in my view, across these islands, and indeed in the best interests of the European Union and its future also."
Mr Coveney said despite some media commentary on the phase one deal struck between the UK and the EU, there was no uncertainty over what had been agreed in relation to the alignment of regulations in key economic sectors on both sides of the border after Brexit.
He said other EU nations remained "unstinting" in their support of Ireland's stance on that issue.