EU membership referendum will be UK-wide poll
The British Government has ruled out holding separate referenda in Northern Ireland, Wales and Scotland on EU membership.
A UK-wide poll is due by 2017 and Sinn Fein has said a Westminster-driven exit agenda would be bad for Northern Ireland.
Europe Minister David Lidington addressed a meeting of the British Irish Parliamentary Assembly (Bipa) in Cheltenham, Gloucestershire.
He said: "It will be clear how people vote in Northern Ireland, Wales and Scotland because we will count on that basis.
"It is the UK that is the member state of the EU, it is right that this decision is taken on the basis of the UK as a whole."
Sinn Fein Stormont Assembly member Barry McElduff said Northern Ireland was a net recipient of EU aid, with fishing and farming particularly vulnerable to any withdrawal.
He added: "There seems to be a Westminster-driven agenda which will be bad for the North of Ireland as we share an economy with the rest of Ireland."
Prime Minister David Cameron has said he will campaign for the UK to remain in the EU if he secures meaningful change, including increased competitiveness.
The British Government wants to ensure it is not discriminated against by remaining outside the euro.
But Mr Lidington acknowledged: "Our timetable for referendum by the end of 2017 means that you just cannot treaty negotiation and 28 national ratifications within that timeframe."
He said he was looking at approaches taken by Ireland and Denmark in the past.
"You would need to have an assurance that this (renegotiation) was being treated as binding.
"What we are offering is a grand bargain, a fiscal compact to be written into a treaty within five years."
Frank Feighan TD, Irish co-chair of the BIPA, said Ireland's experience of referenda was that people did not always answer the question they were asked.
On the Republic's border with Northern Ireland he said: "I don't think anybody would like to see a European border on the island of Ireland."