It would be difficult for Ireland to remain in the euro zone if voters reject a proposed new EU fiscal treaty, European Affairs Minister Lucinda Creighton said on Monday.

If we somehow decided to opt out of that and allowed the other 16 member of the euro zone to progress and try to find a solution without us, I think it would make it almost impossible for us to continue as part of the currency union, Creighton told state broadcaster RTE.

European leaders are expected to agree on the fiscal compact to tighten budget rules on Monday. The Irish government will decide on whether to hold a referendum on the treaty within weeks, she said.

Irish citizens, who are entitled to vote on any major transfers of powers to Brussels, are seen as one of the biggest obstacles to overhaul of the bloc. They have twice rejected changes to EU treaties before voting through amended versions.

(Reporting by Conor Humphries; editing by Patrick Graham)