A "Berlin Declaration" marking the EU's 50th birthday will set the goal of putting the 27-nation bloc on a new foundation by 2009.
Berlin is seen as a symbolic venue for the EU party
However, the declaration will not specifically mention the controversial EU draft constitution.
It will speak of "renewing in time for the 2009 European Parliamentary elections the basis on which the European Union is built".
EU leaders are to endorse the text at a special summit in Berlin on Sunday.
Italian Prime Minister Romano Prodi has told the BBC that without a constitution Europe will die - a view that Britain and some other member states firmly reject.
The draft constitution - so far ratified by 16 of the 27 member states - was rejected by French and Dutch voters in referendums in 2005.
The German Chancellor, Angela Merkel, has told Germany's Bild Zeitung newspaper that the enlarged 27-member EU needs a new constitution to streamline decision-making.
Meanwhile in Rome, where the treaty that led to the EU was signed, European Commission president Jose Manuel Barroso said European politicians had to convince citizens that the EU was the best answer to 21st-Century challenges such as globalisation and sustainable growth.
But Czech President Vaclav Klaus told BBC News the failure to agree on a constitution had not caused a crisis in the EU.
"The people who want to accelerate the unification process are in a hurry and normal people in Europe are not in a hurry," he said.
He said the secrecy surrounding the text of the Berlin Declaration was "ridiculous" and an example of an EU tendency to push decisions through without proper debate.
However, he said he was not going to undermine the summit.
Britain, the Czech Republic and Poland are particularly wary of efforts to revive the constitution.
Berlin's big bash
Berliners are being invited to a party thrown by the EU to celebrate the 50th anniversary of the Treaty of Rome.
A highlight will be an all-night clubbing extravaganza, in which ravers can hop between 35 Berlin nightclubs for an EU-subsidised 12 euros (£8).
This two-euro coin has been minted to mark the 50th anniversary
There will also be free bratwurst and beer, and museums will open all night.
The two-day party, on 24-25 March, is being held in Germany because the country currently holds the rotating presidency of the EU.
Berlin - a formerly war-torn and divided city - is also seen as a symbolic venue in which to celebrate the modern unity of Europe.
Chancellor Merkel, French President Jacques Chirac and British Prime Minister Tony Blair will attend a performance of Beethoven's 5th Symphony by the Berlin Philharmonic, followed by a banquet and a firework display.
The general public, meanwhile, will be treated to a free open-air concert near the Brandenburg Gate by bands from all over Europe.
They include veteran English rocker Joe Cocker, Scottish folk band The Unusual Suspects, and Outlandish, a Danish-Moroccan trio.