Checks on live animals and animal products from Britain as they arrive at ports across the island of Ireland are being planned in the event of a no-deal Brexit, Taoiseach Leo Varadkar said yesterday.
The Government has insisted it will not impose any restrictions along the border if the UK quits without a transition agreement.
However, Mr Varadkar said for the first time checks would have to be made somewhere to protect the EU single market.
"The kind of things that we're looking at and proposing, for example, is that the entire island of Ireland will be treated the same when it comes to agriculture or food and that any checks would happen at the ports," he told Newstalk.
"That would mean Britain accepting that Northern Ireland is being treated differently.
"The other things obviously are checks at business level and random checks and controls, and we'll have to have a lot more of them anyway because of smuggling."
Ireland is in talks with the European Commission over how it could make the necess- ary checks without reimposing controls on the 500km border, which was controlled by military checkpoints until the Good Friday Agreement was signed in 1998.
Any checks between Britain and Northern Ireland would be resisted by the DUP, which props up the Conservative government in London.
"This is not a good solution, this is vastly inferior to what we negotiated with prime minister Theresa May and is vastly inferior to the North's current model," Mr Varadkar said.
The impact of a no-deal Brexit on Northern Ireland would be harder than on any other part of Europe, he warned, and the so-called backstop in the proposed Brexit deal remained the best compromise.
The backlash in the UK parliament to the agreement led to its rejection.
That led to Mrs May being forced out as leader of the Conservatives and will ultimately result in her being replaced as prime minister by Boris Johnson or Jeremy Hunt.
Mr Varadkar said the next British prime minister will face a "very serious reality check" over Brexit on taking office.
He rejected as "incorrect" a claim by the leading candidate, Mr Johnson, that the border issue could be resolved in a transition phase.