Simon Coveney says the UK 'doesn't always behave' like it wants a Brexit trade deal.
The Foreign Affairs Minister says it’s no secret that both sides are now running out of time in the talks - saying it's a matter of days rather than weeks.
However, he said he does believe the British government wants to have a deal in place.
The transition period ends at the end of the year, and both the EU and UK would need to ratify any deal to avoid a 'hard Brexit' scenario.
However, negotiations are still continuing - with issues such as fishing and a 'level playing field' remaining sticking points in the talks.
Minister Coveney is heading to France today for talks with ministers there, with Brexit high on the agenda.
Amid reports that French officials have warned they could veto a deal that gives the UK too many concessions, the Foreign Affairs Minister told Newstalk Breakfast the Irish and French positions on Brexit are "very much in sync with each other".
Minister Coveney said finishing negotiations this complex is 'never going to be easy' - but there's "a good chance we can get a deal across the line in the next few days" if the EU holds its nerve.
He praised the EU's chief negotiator Michel Bariner for doing a "phenomenal job" in the talks so far.
Minister Coveney said: "The implications of essentially no deal - in the hope that we find of a way of getting a deal done at some point in 2021 - means we move into a period of significant disruption, cost, stress, tension, and political blame games between London and Brussels.
"From an Irish perspective, we get caught in the crossfires there.
"There is no guarantee that in the absence of a future relationship agreement now... that we will be able to get a future relationship agreement in place at some point in the first half of next year. That's a very dangerous assumption."
He also highlighted reports that the British government is preparing a second piece of legislation which could breach the withdrawal agreement.
Following a similar piece of legislation earlier this year, Minister Coveney suggested such moves are "hardly consistent" with a country hoping to sign off on a positive future relationship with their neighbour.
