Commerzbank is considering the sale of up to €2bn ($2.67bn) of bonds backed by the German government, in what would be an unprecedented move by the bank at a time when the soundness of the country's bank bailout scheme has come under fresh criticism.

Commerzbank, which will complete its acquisition of Dresdner this month, has already tapped the German government's €500bn emergency fund with €8.2bn capital injection and may also draw on state guarantees for €15bn worth of senior debt issuance.