The DUP's Brexit spokesperson Sammy Wilson has accused the Irish Government of pushing for the Good Friday Agreement to be torn up.
Mr Wilson was responding to comments made by Taoiseach Leo Varadkar about the future of Northern Ireland.
Speaking at the Magill Summer School, Mr Varadkar said the question of a united Ireland would inevitably arise in the event of a disorderly Brexit.
Mr Wilson said the Taoiseach was pushing for the principle of consent in the Good Friday agreement to be cast aside, and for a border to be put up between Britain and Northern Ireland.
Asked if he thought some unionists in Northern Ireland were questioning the union given the prospect of no deal, he said he didn’t believe there were.
"There are many unionists who voted to stay within the European Union but that didn't mean they wanted to leave the union of the United Kingdom," he said.
"The kind of shenanigans that we're seeing from the Government in the Irish Republic at present are making them even more determined, that they will not fall under the clutches of a Government which is so clearly hostile to Britain.
"It is the Irish Government who are pushing for the Belfast Agreement to be torn up, the principle of consent to be cast aside and for a border to be placed between Northern Ireland and Britain, the country to which we belong, the country to which is our biggest source of income and source of trade."
"Now that's what is really annoying unionists, this kind of one sided approach that on one hand they want to stand by the Belfast Agreement and the other hand they're prepared to tear up the principle of consent which was the safeguard for unionists in all of this," he added.
Mr Wilson also said whether Britain leaves the EU with or without a deal, people will not notice any changes along the border.
He said nobody has yet explained how Brexit would tear up the Good Friday Agreement, and also said he failed to understand how nationalists would find themselves alienated as a result of Brexit.
Asked if he believed there would be a general election in Britain before the 31 October, Mr Wilson pointed out that Boris Johnson has said there will not be, and said he suspected Mr Johnson would not want to go to the country before a deal had been secured regarding Brexit.
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Sinn Féin Leader Mary Lou McDonald said "there is nothing provocative about wanting a united Ireland" and "the Government has a responsibility to lead from the front in delivering Irish unity".
She said she welcomed the fact that the Taoiseach has acknowledged that the conversation about Irish unity is under way.
"However, saying that the Government 'might initiate' a forum on Irish unity in the event of a no-deal Brexit is not a strong position. We need meaningful action now."
She called for an all-Ireland forum on Irish unity "without delay".
Fianna Fáil leader Mícheál Martin said: "There is an urgent need to focus on arriving at a situation that does not damage economic wellbeing on this island. Leadership in Dublin and London should be reminded that this is not a public political game of oneupmanship. Dialogue between governments should be ramped up less then 100 days until October 31st."