Tony Blair's hopes of becoming Europe's first president are running into mounting opposition across the EU, with Germany determined to stymie the former prime minister.

A "Stop Blair" website run by pro-Europeans has launched a petition against him; a transnational, cross-party caucus in the European parliament is forming to campaign against a Blair presidency; senior officials in Brussels are privately dismissive about the new post going to a Briton; and senior diplomats in European capitals also doubt that Blair is the right person for the post being created under Europe's new reform treaty.

"There was surprise in Berlin when Blair's name came up so soon," said a European ambassador. Chancellor Angela Merkel of Germany admires Blair and has "great personal sympathy for Tony", he added.

"But more generally the German political elite would be puzzled by the idea of Tony Blair. His track record on EU matters is not so great. There is unease about a Briton at the top in that job. And then personally with Blair, there's the Iraq thing."

Sources close to Merkel confirmed her opposition. "He made a lot of fine speeches about Europe but, essentially, stood on the sidelines when it came to concrete steps forward," they said.

The Lisbon treaty now being ratified by EU member states creates a new post of president of the European council, representing and chairing summits of the leaders of the 27 member countries from the beginning of next year for a maximum five-year term. The president's role and powers are yet to be properly defined. EU ambassadors are expected to meet next month to try to come up with a job description.

Praising Blair as "the most European of Englishmen", President Nicolas Sarkozy of France first threw the Briton's name into the ring last October. Blair has chosen not to dispel the reports of his candidacy.

EU officials believe a Blair bandwagon is being rolled out and hope to halt it in its tracks. "The feeling here about Blair is that he never stuck his neck out for Europe," said a senior official in Brussels. "All the political risk he took was transatlantic, always towards Washington, never for Europe. His chances are dim. Merkel is against."

The opposition to Blair feeds on his commitment to the Iraq war, Britain's high rates of Euroscepticism, the government's half-hearted ambivalence towards the EU and Gordon Brown's battles over the past six months to exclude the UK from several key elements of the Lisbon treaty by "defending Britain's red lines" against the rest of Europe.

"This is a treaty that marks quite a serious drift by the UK away from the EU," said a second senior EU official.

"It would certainly help a country to get the job if it decided to opt in," said Hans-Gert Pöttering, the German European parliament head, implicitly criticising Britain's "opt out" of common policy areas such as the euro single currency, the Schengen border-free zone of 24 European states, and other parts of the new treaty.

"Brand Blair" is generally seen as the former Labour party leader's strongest suit - his worldwide name recognition, talent as orator, skilled political salesmanship and that he enjoys influential links in Washington.

One European prime minister told the Guardian this was why he would support Blair against candidates from small EU countries or less well-known politicians. Leaders or former leaders from Austria, Denmark, Luxembourg, and Ireland are mooted in Brussels as potential contenders.

A formal Blair candidacy would gather formidable support among EU leaders - in eastern Europe, from Sarkozy and from Silvio Berlusconi if returned as Italian prime minister. But Blair is opposed by the small Benelux states, is unlikely to be backed by the centre-left government in Spain, and, most importantly, does not have Berlin's support.

Senior social democrats in Brussels said Jean-Claude Juncker, the Luxembourg premier, would be pressed to go public as a rival candidate if José Luis Rodriguez Zapatero is re-elected Spanish prime minister next month, "to stop the Blair bandwagon rolling".

Formally, the post of president is to be decided by a qualified majority vote of EU countries, meaning that Germany, the EU's biggest and most powerful member, could be outvoted. But this is broadly seen as inconceivable.

"You simply cannot impose a candidate against Germany's wishes," said the sources close to Merkel.