German Chancellor Gerhard Schroeder was quoted on Saturday as saying the EU had to find a way for its planned constitutional treaty to enter into force even if Britain or other countries failed to ratify it.
In an interview with Focus magazine released ahead of publication, Schroeder declined to agree with the view that the constitution would be dead if Britons voted against it in a planned referendum.
"I won't even think in this direction. The truth is we have to find a mechanism for the constitution to enter into force even if the ratification process in one or the other country is not yet completed," Schroeder said.
A government spokesman was not immediately available to expand on Schroeder's remark.
EU leaders are due to sign the draft constitution at a summit in Brussels in June. Schroeder's comment indicated he wants it to contain a clause that, as in UN conventions, would allow it to take effect even if some states reject it.
For example, the United Nations' Kyoto treaty curbing emissions of gases blamed for global warming would come into force if Russia ratified it despite already having been rejected by the United States.
EU treaties have until now had to be ratified by all the bloc's members to take effect, a requirement which will be even harder to achieve growth after membership swells to 25 from 15 countries on May 1.
The EU's Maastricht treaty on monetary union and growth was held up for more than a year because Danes initially voted against, prompting changes to the text that secured a "yes" in a repeat referendum.
Similarly, the bloc's current Nice treaty was held up by an Irish "no", which became a "yes" after changes to it.
A UN convention-style clause could up the stakes in any British referendum because the planned charter will for the first time provide a mechanism for countries to leave the European Union.
British Prime Minister Tony Blair's announcement that he would hold a referendum on the constitution re-ignited a debate in Germany about whether it should amend its constitutional ban on referendums in order to do likewise.
In the Focus interview, Schroeder reiterated his opposition to the idea and doubted there would be the necessary majority in parliament to change the constitution.
Germany's parliament last year overwhelmingly rejected a proposal to change the constitution to hold an EU referendum.
Guido Westerwelle, leader of the opposition Free Democrats who launched the failed proposal, said in a newspaper interview on Saturday the party would re-submit a motion to parliament calling for a referendum.