BRUSSELS, Belgium — European Union leaders will take the first step toward drafting a possible EU constitution when they launch a Convention on the Future of Europe at a summit at the Laeken royal palace in Brussels this weekend.

But the ambitious agenda for reforming the 15-nation bloc proposed by Belgian Prime Minister Guy Verhofstadt has met with stiff resistance from Britain, France and Scandinavian countries and is likely to be watered down, diplomats say.

"Verhofstadt has taken the risk of opening immediately a war that should not have been fought until 2004," one minister said.

"Belgium is looking for an unnecessary fight at Laeken. He is asking leading questions," a senior EU diplomat agreed.

Belgian officials dismiss forecasts of a battle, saying Verhofstadt is "fine-tuning" the text to take account of comments he received on a tour of EU capitals.

At issue is what a yearlong advisory Convention of national and European parliamentarians, representatives of member governments and candidate countries and the European Commission, should debate when it convenes next March.

The aim is to ensure the Union can function effectively when up to 10 new members join in around 2004. That means simplifying the EU treaties, clarifying the division of powers between Brussels, member states and region and giving national parliaments a clearer role in EU affairs.

The summit will also appoint a president of the convention with the crucial twin tasks of managing a potentially unruly and wide-ranging debate and selling its conclusions to EU leaders.

The convention, which will meet in public, is due to make proposals for the next overhaul of the EU's founding treaties in 2004, but national governments will have the final say.

There are two declared candidates — former French President Valery Giscard d'Estaing, one of the fathers of the European Monetary System in the 1970s, and former Italian Prime Minister Giuliano Amato, whose negotiating skills are widely respected.

Critics say choosing the 75-year-old French patrician would send a "back to the future" message unlikely to revive flagging public enthusiasm for European integration.

Amato may be thwarted by the fact that another Italian, Romano Prodi, heads the European Commission.

Diplomats say outgoing Dutch Prime Minister Wim Kok, who repeated publicly on Monday he did not want the job, would be most leaders' favourite if he made himself available. Former Finnish President Martti Ahtisaari is a possible compromise choice if the summit is deadlocked.

Verhofstadt has been touring European capitals with a draft declaration raising controversial "federalist" questions such as the direct election of the European Commission president and a more systematic use of majority voting in decision-making.

Such ideas are anathema to more Eurosceptical member states.

France was unhappy with the critical tone of the preamble on the EU's current shortcomings and the loss of public confidence, illustrated by recent referendum defeats in Denmark and Ireland.

Britain, France and Sweden all insisted that the Convention should merely draw up options, not vote on recommendations.

Given French and German support, the Convention is likely to call for a European constitution, although Britain is unenthusiastic about that prospect.

The leaders will only receive a revised draft of the Laeken declaration during the summit on Friday afternoon, a few hours before they are due to debate it at dinner.

But Belgian officials played down forecasts of a clash as severe as the one in 1991 when ministers tore up radical Dutch proposals for EU integration and returned to a previous draft.

"We're not the Dutch. We're Belgians. We're natural consensus builders," one said.