Irish Prime Minister Leo Varadkar said Ireland would not accept an economic border with Northern Ireland after Brexit and urged Britain to come up with alternatives in an unusually blunt statement.
"As far as this government is concerned there shouldn't be an economic border. We don't want one," said Varadkar, who came to power last month.
He warned Ireland would not "design a border for the Brexiteers" and said that the onus was on Britain to come up with proposals since it had created the problem by voting to leave the European Union.
"It's Britain that has decided to leave and if they want to put forward smart solutions, technological solutions for borders of the future and all of that that's up to them," he told Irish media.
Some British ministers have suggested the installation of an "smart" and "invisible" border including cameras and pre-registration checks for trucks carrying goods.
"What we're not going to do is to design a border for the Brexiteers because they're the ones who want a border," Varadkar said.
The border between Ireland and Northern Ireland is currently open as both countries are in the EU, with a free flow of goods and tens of thousands of people crossing it every day to work on the other side.
The Irish border issue is one of three key Brexit problems -- along with the divorce bill and the status of EU nationals living in Britain -- that Brussels and London have to resolve before moving on to negotiations about future trade ties.
Varadkar said that an economic border no longer existed in practice and he was keen to keep it that way.
"We're not going to be helping them to design some sort of border that we don't believe should exist in the first place," he said.
While acknowledging the predicted negative impact Brexit will have on Ireland's economy and society as a whole, Varadkar also warned of dire consequences for Britain depending on the form of border imposed.
"Let them put forward their proposals as to how they think a border should operate and then we'll ask them if they really think this is such a good idea because I think it will have a very severe impact on their economy if they decide to go down that route," he said.
Varadkar also expressed frustration with the British government's stance on Brexit talks, saying that "if anyone should be angry, it's us, quite frankly".
However, he also said his government would continue to try to find solutions to "minimise the damage" to relations between the two countries.
Ireland's Foreign Minister Simon Coveney also ruled out mooted British proposals to employ new technology as an alternative to the reintroduction of customs posts.
"We have a border that is 500 kilometres (XXX) long. There are 400 road crossings along that border," he told RTE, Ireland's national broadcaster.
He dismissed "anybody that suggests to me that we can solve this problem by putting cameras on that border or having some kind of pre-registration process for goods and services that are crossing the border.
"I don't think this is the approach we should take," he said.