Irish Prime Minister Brian Cowen promised his EU partners Wednesday to come up with an action plan by December on the best way to move ahead with the bloc's stalled Lisbon Treaty.

"By December, it is my aim that we will have identified the necessary steps that need to be taken next year," he told EU leaders at a summit in Brussels.

"I look forward to returning here in December with a view to our defining together the elements of a solution and a common path to follow," he said.

Ireland sent shockwaves through Europe on June 12 when voters rejected the reform treaty in a referendum. It was the only country in the 27-nation bloc to hold a popular vote, although all must ratify the text before it can take effect.

Apart from Ireland, only Sweden and the Czech Republic have yet to ratify the text, and they will do so via the parliamentary route.

The crisis, which recalls the rejection of a full-scale constitution by French and Dutch voters in 2005, ruined the original plan to get the treaty up and running by January 1, 2009.

The Lisbon treaty, drawn up to replace the failed constitution, would introduce an EU president and new foreign policy supremo and cut the number of national vetoes in EU voting.

Measures in it are designed to streamline the creaking institutions of the EU, which is now operating under rules designed before the "big-bang" of 2004 which brought 10 mainly ex-communist Eastern European nations into the fold.

EU leaders had pledged to try to ratify the treaty before European Parliament elections next year, but senior European officials have since said they don't expect it to enter into force before 2010.

"I am extremely mindful that there are important milestones in the course of 2009 which require clarity at an early date," Cowen told the leaders.

"We will continue to work with our partners to ensure that we can overcome the uncertainty that currently exists."

Fifty-three percent of voters in Ireland rejected the treaty, and Cowen said that many had done so because they could not understand it, while others did not feel concerned by the European project.

"It is becoming increasingly clear that this applies not only to the Lisbon treaty itself, but more generally to the EU and how it functions," he added. "This is something that must concern us all."

Cowen accepted that other EU nations did not want to renegotiate the text but he insisted, "we will have to obtain a satisfactory response to Irish concerns if we are to find an acceptable way forward."

When asked whether Ireland would call for a referendum in its action plan in December, Foreign Minister Micheal Martin would only say: "We will bring clarity to the situation in December, one way or the other."

The president of the European Parliament, Hans-Gert Poettering, said he expected in December "guidance from the Irish government, to know where we are headed".

EU leaders had hoped to avoid holding the assembly elections under the existing treaty rules -- Lisbon would have changed the parliament's makeup -- fearing that the bloc's institutional woes would undermine voter confidence.