The Minister for Foreign Affairs Dermot Ahern said it is "likely" that the Government will hold a referendum on the EU treaty negotiated in Germany yesterday.
He said the Government would be seeking the Attorney General's advice on the matter.
Mr Ahern said: "Given the fact that there was strong legal advice that the draft constitution which was agreed in 2004 would require a referendum in Ireland and given the fact that these changes haven't made any dramatic change to the substance of what was agreed back in 2004, I think it is likely that a referendum will be held but we have to take the Attorney General's advice in that respect.
"Ireland over the years has tended to err on the side of caution in relation to this because ultimately it is the people who should decide," he added.
Speaking on RTÉ radio this afternoon the Minister said that there was a real possibility that Ireland would be the only EU country to hold a referendum on the treaty.
Mr Ahern added that he was "very happy with the outcome" of negotiations on a new EU treaty to reform the bloc's institutions.