Brexit represents only way to ensure orderly UK withdrawal: Ireland foreign minister Coveney

Irish Prime Minister Leo Varadkar on Wednesday rejected Britain's bid to reopen negotiations less than two months before it is due to leave the European Union, echoing similar comments from EU leaders.

"As (EU Council) president (Donald) Tusk said yesterday, we are not offering a renegotiation and renegotiation is not on the table. There is no grounds to organise an emergency summit," Varadkar said in the Irish parliament.

British MPs have comprehensively rejected the Brexit deal as it stands, but on Tuesday said they could back it with an alternative to its controversial backstop clause.

The backstop would keep the Irish border free-flowing but could lock Britain indefinitely into EU trade arrangements.

A majority of British MPs want it replaced with "alternative arrangements" in order to back a deal and stop the UK crashing out of the EU on March 29 with no deal.

"I do not know what those alternative arrangements are," said Varadkar, who was due to have telephone talks with his British counterpart Theresa May later Tuesday.

"We've been down that track before and I don't believe that such alternative arrangements exist. And that is why we have the agreement that we have now.

"The only way I believe we can avoid a border, physical infrastructure... is through full regulatory alignment," he said.

Meanwhile, Irish foreign minister Simon Coveney said the Brexit deal "represents the best way, the only way, to ensure an orderly UK withdrawal".

He said the EU was committed to exploring and trying to find alternative border arrangements with the UK to replace the backstop in the future.

The insurance policy would kick in if nothing better emerges by the end of the proposed Brexit transition period, which concludes at the end of 2020, to avoid a hard border and physical checks and controls.

"This has been explored endlessly in the negotiations over the last two years. We have seen no alternative arrangements that meet this essential threshold," said Coveney.

"And we need a backstop or insurance mechanism based on legal certainty, and not just wishful thinking.

"We have less than two months to go now until Brexit happens on March 29. We are, quite simply, running out of road."