The European Union is not ripe for a single financial regulator, Bundesbank Vice President Juergen Stark said in a newspaper article published on Saturday.
Writing in Germany's Frankfurter Allgemeine Zeitung on the challenges facing regulation of global financial markets, Stark said a central supervisor would require EU governments to give up more sovereignty and harmonise national legal systems.
A central supervisor would also not do justice to differences in countries' financial sectors, he added.
"To guarantee stability of Europe's financial system and to integrate its markets we need to harmonise supervisory standards and have close co-operation between authorities," he wrote.
EU governments recently agreed to create two new regulatory committees covering the banking and insurance sectors to sit alongside a similar group already overseeing securities markets. But the committees are composed of national regulators.
In recent negotiations over an EU constitution, governments made no change to rules that would require a unanimous agreement among the EU's 25 member states to give a bigger supervisory role to the European Central Bank.
Non-eurozone member Britain has long opposed making it possible to give more powers to the ECB via majority voting.