Ireland, as European Union president, has circulated a new compromise proposal on the bloc's constitution aimed at overcoming Polish and Spanish opposition to the charter, diplomats said tonight.
The idea, a sort of emergency brake on majority decisions, has been circulated to several governments, and the Taoiseach, Mr Ahern will discuss it with the EU's big three - France, Germany and Britain - on his tour this week, they said.
"This is an informal written proposal," one EU government official said.
Mr Ahern is trying to forge a compromise on how voting power will be allotted among the EU's 15 old and 10 new members in time for a June 17-18th summit which is due to clinch a deal.
Mr Ahern has already visited 17 of the 24 EU member states. Today and tomorrow he will meet the leaders of France, the UK, the Nethelands, Belgium, Luxembourg, Germany and Denmark.
A previous attempt to agree on a new rulebook for the bloc, to enable it to keep functioning after enlargement last month by taking most decisions by qualified majority voting rather than unanimity, collapsed in December over the voting weights issue.
The Irish proposal focuses on adding a "safety valve" to the majority decision-making by allowing a group of states that face being outvoted on a sensitive decision to delay it and raise the majority threshold needed to approve it, the sources said.
This would be modelled on what EU insiders call Ioannina compromise, worked out in 1994 to solve Britain's concerns about being outvoted when Finland, Sweden and Austria joined in 1995, changing the balance of power in the EU.
It allowed the minority to call for further negotiation to seek a broader majority. But it has never been invoked.
Diplomats said Poland, the biggest of former ex-communist states that joined the EU, saw the Irish draft as a step in the right direction but that Warsaw would insist on modifications.
EU diplomats see Poland as the biggest obstacle to any deal on voting rights because of its crippling political crisis.
The weak leftist government of acting Prime Minister Marek Belka faces enormous pressure from the opposition not to give up any of the voting power the country was awarded under the EU's Nice Treaty in 2000, which the new constitution would replace.
Polish officials have warned that Mr Belka will not agree to any compromise that could be overturned by hostile parliament, where opposition parties have a majority.
Poland and Spain blocked the EU charter last December because they wanted to maintain their disproportionately high voting power, putting them nearly at par with France and Germany.
Both have since signalled readines to accept a voting system, supported by Berlin and Paris, under which decisions are made by a majority of EU states representing a majority of EU population - a so-called "double majority."