"If this scenario were to become a reality, we would be complying with the regulations established by an organization that we were no longer part of and in which we did not have any participation.
"So, where is the responsibility?"
He added: "The trade unionists who voted remain, they did not do so because they wanted to leave the United Kingdom and it is dishonest and deceptive to portray them as such.
"And they certainly did not vote for the endorsement either.
"While you continue to move savagely by making sure that the endorsement is an insurance policy that nobody wants to refer to as the best of the two worlds, it leaves the impression that there are those who have their fingers crossed behind their backs. United Kingdom will not get a good deal and we will stop paying for support.
"This position is as reckless as those who pursue a difficult Brexit, or even a No-deal."
The British government and the trade unionists in Northern Ireland, where people voted overwhelmingly to Stay, have opposed any solution that could see a regulatory border created in the Irish Sea between Northern Ireland and Great Britain.
The Irish government wants to preserve cross-border trade and peace on the island.
Mr. Swann continued issuing a warning to Taoiseach Leo Varadker and Tanaiste Simon Coveney, saying they should "walk carefully" and accused the Irish Government of working against the United Kingdom instead of doing so.
He added: "Let me also be clear that we want a good relationship with our neighbors in the Republic of Ireland, but it is very difficult to maintain that when we constantly get in our eyes, work with us, not against us."
"So I have a message for Leo Varadkar, Simon Coveney and his colleagues in the Government of Ireland.
"Every day that you trample on the Belfast Agreement and the consent principle, you do more damage to the relationships on these islands."