Northern Ireland is staring into a "Brexit black hole" and a "calamity" that offers no economic, cultural or peace building opportunities, the Stormont finance minister has told an Oireachtas Committee.
Máirtín Ó Muilleoir, Northern Ireland Minister for Finance was speaking before the Oireachtas Jobs, Enterprise and Innovation committee.
The committee has been engaging with witnesses for the last two months on the subject of Brexit.
Minister Ó Muilleoir said that "at the minute north of the Border, we are staring into this Brexit black hole. I see no economic opportunity, no cultural opportunity, no opportunities for community uplifting and no opportunity for peace building in a Brexit.
"I have failed to be persuaded that we are on the cusp of massive opportunities."
Separately, the Nevin Economic Research Institute said in a report published today Northern Ireland would not benefit from remaining in the EU Single Market if the rest of the UK decided to leave.
However, it said there is a case to be made for it to remain in the EU Customs Union.
It also recommends that Northern Ireland seek a derogation from any curbs on free movement of people at UK level, to ensure an open border with the Republic and prevent a sudden worsening of the North's labour market.
The institute says the North has £3.5 billion of annual sales to the Republic, but £12.5 billion sales to Britain, so trying to stay in the EU Single Market when the rest of the UK departs would risk economic self harm.
It says there is an economic case for trying to keep Northern Ireland in the European Customs Union, to ease the regulatory burden on local firms, even though this would mean having customs checks on goods between Britain and Northern Ireland.