The draft EU Withdrawal Agreement flies in the face of UK government commitments on Northern Ireland, DUP deputy leader Nigel Dodds has said.
Mr Dodds met British Prime Minister Theresa May along with his party's Brexit spokesman Sammy Wilson and MEP Diane Dodds earlier today.
He reiterated the party's concerns over the proposed Northern Ireland border backstop.
Mr Dodds said: "The Irish Republic's 'no deal' preparations published just before Christmas have laid bare the nonsense propaganda about a hard border.
"No one wants a hard border between Northern Ireland and the Republic.
"Indeed, its becoming clearer by the day that no one is ever going to construct such a border."
He added: "With this clarity emerging in London, Dublin and Brussels, there is evidently no need for the aspects of the Withdrawal Agreement, which have been so vigorously opposed by a broad cross-section of the House of Commons.
"The Withdrawal Agreement, as currently proposed, flies in the face of the Government's commitments on Northern Ireland as we leave the EU."
The UK Government has said it does not want a hard border re-imposed on the island of Ireland.
Mrs May has also said the country will exit the EU as one United Kingdom.
Mr Dodds said that contrary to pro-EU spin, the border backstop keeping Northern Ireland aligned with the Republic on trade matters is not the best of both worlds.
"It is potentially indefinite in time, would place a barrier between us and our main trading partner in Great Britain and give enormous leverage to the European Union in the negotiations on the future relationship with the United Kingdom."
Mr Dodds said the party would have further discussions with Mrs May and will continue to work with the government in the interests of getting a better deal.
"Brussels must now demonstrate that if it truly cares about Northern Ireland, then erecting a new east-west barrier should be no more palatable than having any new north-south barriers," he said.
Meanwhile, Best for Britain, which describes itself as an organisation attempting to keep the UK open to EU membership, said the DUP had "pulled the rug out" from underneath Mrs May.
It claimed: "Her Brexit deal is dead in the water. If Theresa May can't convince Nigel Dodds and her own party to back her deal after a one-to-one, why should the country support it?
"It irritates Leavers and Remainers alike, and it actively concedes influence over British laws. It's a bad deal. There's only one solution to this nightmare.
"We need to give the public a final say on Brexit with the option to stay and strengthen ourselves within Europe."