The Minister for Foreign Affairs has called on the UK and the EU to "dial down the language" on key Brexit trade issues.
Simon Coveney said the two sides are very far apart on terms such as fishing and the level playing field.
London and Brussels are trying to hammer out an agreement for when the current transition period finishes on December 31st.
Minister Coveney said a post-Brexit trade deal between the UK and the EU is very difficult to achieve but still doable.
Speaking on Sophy Ridge on Sunday, he said there are "real obstacles" to achieving the deal.
He said: "The consequence of not getting a future relationship agreement in place by the end of the year, I think is very significant, for Britain and Ireland in particular, but also for a number of other EU countries as well.
"There is a real reason to get this done."
BREAKING: Irish Foreign Affairs Minister @simoncoveney says UK-EU deal "won't be ratified" if the British government reintroduces parts of the internal market bill struck out by the House of Lords this week.#Ridge pic.twitter.com/OZtMqYmZ2u
— Sophy Ridge on Sunday (@RidgeOnSunday) November 15, 2020
Minister Coveney added: "If the British government is determined to continue with their Internal Market Bill to reintroduce parts of that bill that were removed by the House of Lords this week, then I think this is a deal that won't be ratified by the EU.
"Because there's no way the EU will agree to ratify a new agreement if the British government is breaking the existing agreement that's not even 12 months old and breaking international law by doing that."
He added that the coming days are "move week" as "we've got to make big progress this week".