Sammy Wilson has claimed that no-deal plans published by the Irish government have exposed "Brussels spin" on the Withdrawal Agreement.
Contingency plans revealed by Taoiseach Leo Varadkar include the purchase of land at Dublin port and Rosslare to prevent congestion because of new customs, sanitary and animal health checks at the sea ports.
And the East Antrim MP said that highlighted the true nature of what was planned for Northern Ireland under Prime Minister Theresa May's plan.
He said: "When sanitary and animal health checks are to be carried out between Northern Ireland and Scotland under the Withdrawal Agreement, we are told they are no barrier to trade.
"However, when they are to be carried out between the Republic of Ireland and Wales, under a no-deal Brexit, then they require the purchase of extra land at ports to accommodate the lorries awaiting inspection.
"This lifts the lid on the truth which lies behind the Brussels spin machine."
Irish premier Leo Varadkar also said his government has made "no preparations whatsoever" for a hard border on the island.
Despite the looming possibility of a no-deal Brexit, Mr Varadkar said he felt that if the Irish government made plans to facilitate a hard border it would become a "self-fulfilling prophecy".
He said the draft agreement currently tabled by Mrs May is the key to avoiding physical infrastructure on the border between Northern Ireland and the Republic.
"We are not preparing for a hard border between Northern Ireland and Ireland," he said.
"We have made no preparations whatsoever for physical infrastructure or anything like that."
Mr Wilson said: "The Irish government has argued for a backstop to prevent a hard north-south border. Yet the hard border is absent from their 'no-deal' planning. Their hard border spin has been exposed as nothing short of a Dublin conceived and Brussels delivered mirage.
"Evidently, the Republic of Ireland has always recognised that no hard border would be erected.
"What they really wanted however was that the disruption to trade be kept inside the United Kingdom."
Ulster Unionist peer Lord Empey said that if Dublin had engaged in a consensual rather than a confrontational approach to the border there would have been no need for crisis preparations.
"There is no doubt that the UK leaving the EU creates problems for businesses, but the amount of time and effort being focused on the land border in Ireland is totally out of proportion to the problem, and gives rise to the suspicion that it is being used by Brussels as a point of leverage to pressurise the UK Government. The proposed backstop is a sledgehammer to crack a nut," Lord Empey said.
"London should never have agreed to the sequencing proposal from the EU in the first place; to agree a deal on the border and a deal on finance before the terms of trade were discussed was madness and has led to this mess we are in today."
Meanwhile, the Government is drawing up plans to stop food shortages from affecting hospital patients in the event of a no-deal Brexit, according to official documents.
Doctors and nurses should also be ordered to provide "messages of continuity and reassurance" to patients in the event the UK crashes out of Europe without a Withdrawal Agreement, according to the Department of Health and Social Care paper.
The document, entitled EU Exit Operational Readiness Guidance, was released on Gov.UK yesterday after MPs had left Parliament for the Christmas recess.
It came as Cabinet minister David Gauke said he would find it "very difficult" to remain in Theresa May's Government if there was a no-deal Brexit.
MPs are due to vote on Mrs May's Withdrawal Agreement in January, with no guarantee it will be passed. The Prime Minister is battling to maintain Cabinet discipline as senior ministers set out rival plans for dealing with the potential rejection of her Brexit plan next month.
She has stressed that a no-deal Brexit is a possible outcome if her plan is rejected by MPs.
But Justice Secretary Mr Gauke said: "I think making a conscious decision to proceed with no deal would not be the responsible course of action."
Asked if he could remain in the Cabinet if that became the Government's policy, he told the BBC's Political Thinking with Nick Robinson podcast: "I think it would be very difficult for me in those circumstances."