Commerzbank, which has extensive operations in Poland through its mBank, has already provisioned or made payouts of around 1.7 billion euros ($1.84 billion) to deal with the issue.

Orlopp, speaking at a financial conference, said the uncertainty around the issue "keeps me cautious" but that "by end of this year we should have a clear picture" on where the lender stands on the loans.

The bank has been trying to reach settlements with customers who took out mortgages in Swiss francs.

($1 = 0.9223 euros)

(Reporting by Tom Sims; Editing by Miranda Murray)