German investigators looking for evidence of possible money laundering have searched multiple offices belonging to Deutsche Bank.

A total of 170 officers from the Frankfurt public prosecutor's office, the Criminal Bureau of Investigation (BKA), the tax fraud office and the federal police searched the head office of Germany's largest lender in Frankfurt, among other properties, on Thursday morning.

A total of six properties were searched in Frankfurt, Eschborn and Gross-Umstadt, the public prosecutor said.

It is suspected that bank employees helped customers set up offshore firms in tax havens.

The prosecutor suspects further that proceeds from criminal activity were transferred into Deutsche Bank accounts without the bank flagging the transactions as potential money-laundering cases.

The investigation was launched after evaluation of the explosive Panama Papers tax haven revelations and the previous Offshore Leaks report of offshore bank accounts, according to a government spokesman, Nadja Niesen.

The analysis "gave rise to suspicion that Deutsche Bank was helping clients set up so-called offshore companies in tax havens and the proceeds of crimes were transferred there from Deutsche Bank accounts" without the bank reporting it.

In 2016 alone, more than 900 customers are alleged to have transferred some 311m euros to one such company set up in the British Virgin Islands, she said.

The suspects are accused of failing to report the suspicious transactions even though there was "sufficient evidence" to have been aware of it.

Deutsche Bank confirmed that authorities were "conducting an investigation at a number of our offices in Germany".

"The investigation has to do with the Panama Papers case," the bank said. "More details will be communicated as soon as these become known. We are cooperating fully with the authorities."

Deutsche Bank shares slid sharply after the news broke, and were down 3.75 percent in midday trading in Frankfurt.