French President Jacques Chirac and Spanish Prime Minister Jose Luis Rodriguez Zapatero made a joint appeal Friday to Spanish voters to back the EU constitution, nine days ahead of a Spanish referendum on the mooted text.

Spain will be the first of around a dozen EU states, including France, to put the text to a popular vote on February 20 and Chirac and his host spoke with feeling as they lauded the proposed document, designed to facilitate decision-making in the recently enlarged 25-member bloc.

Chirac, who spoke first, opened with a call for "a massive yes vote which will serve as an example to the whole of Europe.

"Europeans will be more effective thanks to modernised and reinforced institutions ... allowing Europe better to assume its responsibilities," said the French leader, whose fellow citizens are due to hold their own vote by the summer.

"It is by unifying that Europeans will be strong. Without union, they will disappear," Chirac stressed, adding that the text would defend the "European social model."

For Zapatero, the proposed constitution, which requires the backing of all EU member states to take effect, "enshrines the interests of a plural Europe," giving its members "a common identity" while allowing them to maintain their individual identity.

Zapatero, who stressed the issue at hand had nothing to do with party politics but was about Europeans "coming together to make history together", pointed to the "fine example" of Spain's two decades in the Union, a period which has seen the country advance by leaps and bounds.

He insisted a 'yes' vote was synonymous with "prosperity and solidarity" and would banish the concepts of war and dictatorship from Europe.

Latest polls show that 51.2 of the Spanish electorate back the constitution, some ten percent more than in December polls.

Nonetheless, several hundred opponents of the proposed treaty gathered to demand more emphasis on social policy as Zapatero and Chirac made their pitch for an overwhelming vote in favour before some 700 invited guests.

Friday's ceremony opened to the strains of Catalan flamenco singer Ginesa Ortega, daughter of a French gypsy mother and Spanish father.

Missing from the ceremony at Barcelona's Palace of Congress were Italian Prime Minister Silvio Berlusconi and German Chancellor Gerhard Schroeder, who sent messages of support having had to cancel their scheduled attendance suffering from flu.

A spokesman for Zapatero earlier told AFP that Schroeder was "very keen to take part in the Spanish campaign" and "might attend another meeting on the issue in Spain next week."

Since he came to power nearly a year ago, Zapatero, departing from the staunchly pro-Washington stance of his rightist predecessor Jose Maria Aznar, has established close ties with France and Germany.

For Chirac, the Barcelona meeting was an opportunity to sharpen his own pro-constitution message a few months before what promises to be a tough referendum on the issue in France.

Among those countries preferring the parliamentary route, Slovenia, Lithuania and Hungary have already ratified the text, as has the lower house of the Italian parliament, though the Italian upper chamber still has to approve it. The German parliament is expected to debate the constitution in May or June.

Spanish voters are called upon to answer the question: "Do you approve the treaty instituting a constitution for Europe?"