BERLIN/ZURICH (Reuters) - Swiss banks have discovered thousands of accounts opened before 1955 and dormant for at least 50 years, a German newspaper reported on Sunday, saying the move could help reveal where wartime Nazi loot was stashed.

Germany's Welt am Sonntag newspaper said the accounts were being examined under a new Swiss law that requires banks to publish information this year on accounts that were opened at least 60 years ago and have been unclaimed for 50 years.

A spokeswoman for the Swiss Bankers Association (SBA)confirmed the report, saying the accounts in question were from both Swiss and foreign customers, adding that there was no specific Nazi link and the banks were not looking for particular groups.

"This publication is important for the banks as it allows them to search very widely for beneficiaries of the unclaimed wealth before the money has to be handed over to the government," the spokeswoman said.

Unclaimed accounts are a sensitive topic in Switzerland after the World Jewish Congress led a campaign in the 1990s for Swiss banks to return assets of Holocaust victims.

Strict secrecy laws mean that Swiss banks fiercely guard the identity of their clients, a tradition that has come under fire for helping hide tax evaders and which encouraged Nazis to open accounts in the neutral state during World War Two.

The Welt am Sonntag report, published as Berlin marked 70 years since the end of the war, said at least one suspicious account had turned up, opened by a German in 1940 and containing more than 1,000 Swiss francs.

The SBA spokeswoman declined to comment on individual cases, saying the investigation was still under way.

(Reporting by Emma Thomasson in Berlin and Alice Baghdjian in Zurich; editing by Jane Baird)