A man walks past a branch of Commerzbank ahead of the bank's annual news conference in Frankfurtft.com

German prosecutors are investigating whether Commerzbank helped clients to evade taxes via its subsidiary in Luxemburg.

The German bank said in a statement on Tuesday evening that it was co-operating “actively and comprehensively” with the investigations, which it added related to cases from “10 or more years ago”.

“We will investigate these cases internally and deal with them in co-operation with the investigating authorities. We demand absolute transparency that all our clients in Luxemburg have a clarified tax status,” the bank said. “As a matter of principle, Commerzbank rejects business relationships with clients whose tax status is unclear.”

Commerzbank made the statement after the German newspaper, Suddeutsche Zeitung, reported that German officials had searched the bank’s offices in Frankfurt as part of an investigation into alleged tax dodging. Prosecutors in Cologne did not respond to requests for comment.

In recent years, German authorities have taken an aggressive approach in their efforts to clamp down on tax evasion, carrying out several raids and even buying some CDs containing confidential client data.

The news of the latest investigation comes at a time when the question of how to combat tax evasion is once again at the top of the international agenda.

Over the past two weeks, Europe’s biggest bank, HSBC, has been engulfed in a political firestorm following allegations that its Swiss private bank helped thousands of clients to dodge the taxman.