Merkel in Dublin

"What I can say looking back not least on my own life is that unification and the creation of the EU is the best thing that has happened to Europe in its long history," Merkel told a forum of politicians and campaigners in Dublin.

"To my mind the Lisbon Treaty offers the best preparation for Europe's future. Let us all make sure that the European Union continues to flourish," she said.

"To the skeptics, I can only say that if everything remains as it is now, your concerns will definitely not be better addressed."

Ireland is the only one of the 27 EU member states holding a vote on the treaty, and rejection could in theory block it and plunge the union into fresh chaos.

Rally attempt

Merkel's speech to the National Forum of Europe kicked off a pro-European assault on Ireland this week, with European Commission President Jose Manuel Barroso visiting on Thursday to rally votes in favor of the treaty.

The chancellor said the Lisbon Treaty, which was hammered out last year to replace the draft constitution rejected by French and Dutch voters in 2005, increased the power within the EU of smaller states such as Ireland because a new majority voting system allowed them to block bigger countries such as Germany.

"The new majority voting system in the Lisbon Treaty is actually more of a problem for the bigger states," she said.

"Today even a big country such as Germany will simply also have to give up on some of its interests," Merkel said.

Still undecided

A poll published Monday showed that a vast majority of Irish voters remain undecided on the treaty and less than a third plan to vote at all.

The survey, published in the Irish Sun newspaper, found 28 percent have decided to vote "Yes", 12 percent will vote "No" and 60 percent are still to make up their minds.

Irish Prime Minister Bertie Ahern has said he will stand down in May to fight allegations of financial irregularities.

His likely successor, current Foreign Minister Brian Cowen, has vowed to make securing a "Yes" vote his first priority.