Irish voters would narrowly back a proposed European Union treaty to tighten budget rules if it was put to a referendum, an opinion poll showed on Saturday, but a quarter of those questioned said they were still undecided, Reuters reported. European leaders are expected to agree on the fiscal compact on Monday in a bid to regain market confidence in the public finances of the 17 countries sharing the euro. 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. Forty percent of the 1,000 people questioned in the Sunday Business Post/Red C poll said they would vote in favour of the treaty, with 36 percent opposed. Twenty-four percent said they did not yet know how they would vote. The government has said it will seek legal advice before deciding whether to hold a referendum, but 72 percent of those polled said the treaty should go to a vote. EU officials agreed to the new treaty in December, aiming to push ahead with deeper economic integration and tackle a euro zone debt crisis.