Taoiseach Enda Kenny said yesterday the Government won't be able to decide until March if a referendum is needed to pass tough new EU budgetary rules.
Mr Kenny has invited the leaders of the opposition to be briefed on the outcome of the EU summit.
Fianna Fail leader Michael Martin, Sinn Fein president Gerry Adams and Technical Group chief whip Catherine Murphy will get the briefing at 8am this morning, before the weekly cabinet meeting.
The Taoiseach said a lot of detailed work on the wording of the deal would have to be done before the Government could make a decision on a referendum.
Following British Prime Minister David Cameron's decision to opt-out from the package, Mr Kenny said his preference was that the 27 member states would be involved in the discussion.
"Ireland is very interested in seeing that the prime minister retains a deep interest in expanding the single market," he said.
Mr Kenny said he was not suggesting Ireland would be used as a conduit for back channel discussions between Britain and the rest of the EU. "We are anxious that every country be involved in the process."
EU Commissioner Olli Rehn yesterday insisted that the agreement for stricter budget rules could work, even if the UK stays outside the deal.
In Brussels, Mr Rehn said countries that reached agreement on closer co-operation would be able to rely on European institutions like the commission, council and parliament for support. He rejected the UK government's claim that the "treaty within a treaty" would not work.
He said the agreement reached was "bold, effective and legally viable."
"Claims the treaty is not enforceable are simply unfounded," he added.
Mr Rehn said the plan would complement the "six pack" budget rules that come into force across Europe today.
The "six pack" is a new set of EU rules to monitor and correct budget deficits, nation debt and government spending.
It was signed off on by the European Parliament and all 27 member states back in October, but is already seen by many as too weak to restore confidence in the eurozone. That led to last Friday's call for even tougher rules.
Meanwhile, NCB Stockbrokers said the deal signed on Friday would mean higher taxes and more cuts for Ireland, over a longer period.
It said the new EU plans for budget discipline would leave this country facing additional budget measures over the coming years. Ireland would not meet the new criteria by 2015, even if we fully complied with the bailout, NCB said.