DUP Brexit spokesman Sammy Wilson has accused Taoiseach Leo Varadkar of behaving "in an abominable way".
He said the Taoiseach had made empty threats in suggesting that electricity could be cut off in Northern Ireland and that he was going to send troops to the border.
"That kind of rhetoric has not helped relations between Northern Ireland and the Irish Republic," he said.
Mr Wilson said that he had worked hard within the Stormont Government to normalise relations between Northern Ireland and the Irish Republic.
“For whatever reason, the current Taoiseach has set relations back by years.”
Speaking on the Claire Byrne Live programme, Mr Wilson said a no-deal scenario will be much more damaging to the Irish economy than to the UK economy.
“A small Irish economy will not be able to stand the impact of Britain leaving and the huge imports which Britain brings from Ireland being cut off,” he said.
Mr Wilson told the programme that a larger proportion of Irish exports go to Britain than go to the EU.
In reality, according to the latest figures from the Central Statistics Office (CSO), 11 per cent of Irish exports go to Britain (€14.1 billion). Half (€71 billion) go to the EU.
“It just seems absolute madness,” he said. “Your Government has rushed headlong down a route that puts a barrier between not only Northern Ireland and GB which is our main market, but between Ireland and GB, which is your main market.”
He predicted that Ireland will be the next small nation in Europe to suffer the "overbearing power of France and Germany".