Martin McGuinness believes the implications of a UK withdrawal from the European Union would be “absolutely enormous” for Northern Ireland.
A referendum will be held on whether to remain in the EU on Thursday, June 23.
At Westminster yesterday, British prime minister David Cameron presented his argument for staying.
He outlined the details of the deal he agreed with other European leaders last week.
Mr McGuinness has queried how a withdrawal would affect agreements made during the peace process.
The North’s deputy First Minister said: “Anybody that has examined our relationship in the North with the EU over the course of many years can’t fail to recognise the enormous benefits there have been for the community and voluntary sector, farmers and business community.
“I believe that right across the community - unionist and the broad nationalist/republican community - the majority of people place great value on our membership of the European Union and they want that to continue.
“The other implication that we have to consider is given the fact that there appears to be an intention in Europe to tighten borders. How, for example, will that have an effect on people who travel from Belfast to Dublin, from Derry to Buncrana, from Newry to Dundalk?”
The deputy first minister also called on Northern Ireland Secretary of State Theresa Villiers to resign following her public support for a UK exit from the European Union.
Meanwhile, SDLP leader and Foyle MLA Colum Eastwood says the referendum will be “one of the most important votes faced by people in Northern Ireland in decades.”
“It is vital that a strong and positive campaign is conducted to remain in Europe,” he said. “The SDLP’s campaign has already begun and I am calling on Sinn Féin, the Alliance Party and the Green Party to do their utmost in ensuring that Northern Ireland delivers a strong vote to remain in the EU on June 23. I would also urge the Ulster Unionist Party to do what is best for farmers and families and campaign for an ‘In’ vote.”
Mr. Eastwood hailed the billions of pounds that Europe has invested in farming incomes, in peace monies and in infrastructure projects in NI.
“We know what being part of the EU looks like,” he added. “I’m confident that people in the North will vote to retain the safety and opportunity offered by remaining in the European Union.”
The SDLP leader also branded the ‘Leave Campaign’ as a ‘pick and mix of extremists and eccentrics’.