FRANKFURT (Reuters) - Deutsche Bank played only a secondary role as a so-called correspondent bank to scandal-hit Danske Bank, limiting what it needed to know about the people behind the transactions, the German lender's regulation chief said on Wednesday.

Danske, Denmark's largest bank, is facing allegations of money laundering through its Estonia branch. Deutsche as a correspondent bank helped process up to $150 billion in suspicious payments, a source with direct knowledge of the case has said.

Deutsche Bank took action once it noticed suspicious transactions, its Chief Regulatory Officer Sylvie Matherat said at a conference when asked about the issue.

Matherat's comments amount to an effort to distance Deutsche from the affair as Germany's financial markets watchdog - BaFin - reviews whether to open a formal investigation into its role.

Matherat said that Deutsche's relationship with Danske lasted eight years before Deutsche ended it. Matherat declined to comment on the volume of transactions Deutsche executed for Danske.

She said that Deutsche conducts about between $400 billion and $450 billion in transactions every day and monitors them closely.

(Reporting by Andreas Framke; Writing by Tom Sims; Editing by Thomas Seythal/Keith Weir)