Minister for Foreign Affairs Simon Coveney has told the Dáil the Brexit withdrawal agreement is "not going to be reopened".
Mr Coveney said it was not a draft and was not open for renegotiation.
He told Fianna Fáil Brexit spokeswoman Lisa Chambers that the only document that would change was the political declaration about the future relationship between the EU and the UK.
He also said that many people had been too quick to assume the worst. They should instead be looking at ways to talk it up and maximise support for the deal and that was what British prime minister Theresa May was doing.
During questions on foreign affairs the Tánaiste said the document on the political declaration was expected to be at least 20 pages when the wording had been completed, which they expected to have later on Tuesday night or Wednesday evening. Mr Coveney said they had a “short, seven-page skeleton document last week”.
But he stressed that even if EU leaders backed the agreement at their meeting in Brussels on Sunday, and if it was backed by a majority of MPs at Westminster, they had at least two to three years of negotiations ahead on the future relationship.
The Brexit agreement is sensitive and difficult, he said. “It’s a compromise on both sides.”
Ms Chambers had expressed concern that comments in the House of Commons last week suggested that this was not the final agreement and “certain aspects of it were only temporary”.
The Tánaiste told her that “this is a text that has been agreed between the negotiations teams, it has been agreed by the British government. So to that extent, it is not a draft text, it now the text, and it is not going to be reopened.”
But it was a process “where Ireland will continue to have to be vigilant to mitigate against unintended consequences of the fallout of Brexit”.
He also warned that “many people have been far too quick to start jumping past the time when the parliament in Westminster makes the decision and are assuming the worst”.
“We should not do that. We should spend the next couple of weeks explaining to people and reassuring them as to what is in the deal,” he said.
“It is a good deal for Ireland, the UK and the EU. It captures the complexity of an economy the size of the UK leaving the European Union and tries to deal with a whole series of competing and complex questions to do with that.”
“Instead of focusing on contingency after a failed vote in the House of Commons, we should be talking about how we talk this up to maximise the chances of it getting support in the House of Commons, which is what the prime minister is doing.”