European Union leaders have failed to reach agreement on a constitution at a crucial summit in Brussels.
Berlusconi offered four possible solutions to Spain and Poland
The talks broke down over the voting rights states will have after the EU expands from 15 to 25 members in May.
Poland and Spain insisted on keeping the voting rights already secured, while France and Germany want a system to reflect their bigger populations.
The BBC's William Horsley in Brussels says this looks like a disaster for the EU and the future is now uncertain.
Italian Prime Minister Silvio Berlusconi said there was "total disagreement" on voting powers.
The leaders are preparing to leave Brussels after two days of sometimes bitter exchanges.
Speaking to reporters after the summit broke up, UK Prime Minister Tony Blair backed the decision to abandon the talks, saying the bloc should take time to find the "right agreement".
Swedish Prime Minister Goran Persson said talks on the constitution were unlikely to resume until 2005.
He said the EU would ask Ireland, which takes over the presidency in January, to hold talks to suggest a way forward.
Irish Prime Minister Bertie Ahern said he would give a progress report at the next summit in March.
Our correspondent quotes one official as saying that France forced the breakdown of talks by refusing to consider any compromise on the voting issue.
The failure to reach an agreement could deepen a split within Europe about the speed of integration.
French President Jacques Chirac told reporters after the summit that he wanted to see a "pioneer group" of countries that wanted to push ahead with integration.
Number of commissioners
National vetoes on foreign, defence and taxation policy
Extent of European Parliament's influence on EU budget
"It would be a motor that would set an example," he said. "It will allow Europe to go faster, better."
German Chancellor Gerhard Schroeder also said a definitive failure to agree a constitution could lead to a "two-speed Europe".
A summit agreement in Nice three years ago gave Spain and Poland - one of the new members - almost as many votes each as Germany, despite them having smaller populations.
Warsaw and Madrid say the subsequent constitution proposals significantly diminish their power, and are unacceptable.
Saturday saw Mr Berlusconi - as host of the talks during Italy's tenure of the EU presidency - present four alternative proposals to Spain and Poland in an attempt to break the deadlock.
But Polish Foreign Minister Wlodzimierz Cimoszewicz signalled his country's refusal to give ground on the voting rights issue.
"If it's not possible to agree, we shall wait. We're talking about compromise or domination," he said.
All 25 leaders must approve the proposed constitution. However, an agreement is not needed in order for the enlargement to go ahead.
The constitution, drafted over 17 months by a special convention, introduces a "double majority" system of voting.
It means a vote is passed when it has the support of 50% of countries, representing 60% of the EU's population.
Medium-sized countries like Poland and Spain say the system favours big states - like Britain, France and Germany - and the very smallest nations.
Regardless of any agreement that might have been reached this weekend, the voting rules under the existing Nice treaty continue to apply until November 2009.