The Irish government has rejected any suggestion that a future Stormont executive could veto aspects of the border backstop.
Deputy premier Simon Coveney was reacting to a UK Government proposal that, if the backstop came into operation, the devolved legislature in Belfast would have to agree to any subsequent changes to EU laws impacting on it.
Mr Coveney told BBC Radio Ulster: “Let’s not forget what we are talking about here is a withdrawal agreement which is an international agreement between the UK as a whole and the EU as a whole, it isn’t a bilateral agreement between Ireland and Britain.
“And so from that point of view, I don’t think a Northern Ireland executive can hold a veto over the implementation of an international treaty between the UK and the EU.”
Mr Coveney is in Belfast to meet politicians and business leaders to discuss the Brexit impasse.
There was confusion over whether his schedule would include a meeting with the DUP after he claimed the party had declined an offer to hold talks.
However, DUP leader Arlene Foster swiftly responded, insisting she was willing to meet the Tanaiste.
“The party has had useful discussions with the Irish government in the past,” she said.
“I’m happy to meet with the Tanaiste later today in Belfast.”