Taoiseach Leo Varadkar has said he expects Brexit to be centre stage again following the breakdown in talks in Britain between the Conservative and Labour parties.
Labour has pulled out of cross-party talks, with leader Jeremy Corbyn writing to British prime minister Theresa May and referring to a lack of progress and government instability.
Speaking in Tullamore, Co Offaly on Friday evening, Mr Varadkar said a no-deal Brexit could result in customs checks at the Border.
While the Government’s preference for checks at the ports and airports remained, they could be required elsewhere in a worst case scenario.
“I’m not assuming there will be divergence in regulations between Northern Ireland and Ireland,” said Mr Varadkar.
“If we end up in that scenario we have to examine what kind of checks will be necessary and where they will happen. Although it’s always been my view they should happen at the ports.”
Mr Varadkar added: “It’s so much easier to do these checks at the ports in Northern Ireland than it would be along a land border with 300 crossings.”
Mr Varadkar, who was speaking before a European Parliament and local election rally, appealed to any Irish businesses which had not already done so to make preparations for Brexit. The Government would continue to fight for access to other international markets, he said.
“We’re not making any preparations for a hard border between Northern Ireland and Ireland. I don’t think we should,” he said.
“A no-deal Brexit would have very serious consequences for Ireland but we are prepared for it, as prepared as we can be.”
The backstop was the best way to protect Ireland and ensure Northern Ireland continues to align to single market rules and customs.
He said the necessary legislation had been passed by his Government and preparations will be stepped “up a gear”.
“I still think there can be and will be an orderly withdrawal but we have to be prepared for the worst,” he said.
Addressing the rally, where he urged voters to back Andrew Doyle in the European Parliament constituency of Ireland South, Mr Varadkar said the Brussels- and Strasbourg-based assembly will be especially crucial in the coming months because it will have to ratify any Brexit withdrawal agreement.
