There could be mergers and acquisitions in the German banking sector to offset the costs of low interest rates, a member of the European Central Bank's executive board told CNBC on Monday.

While the economy is strong, margins and profitability at German banks have been squeezed by low interest rates. There have been reports that Deutsche Bank and Commerzbank were considering a merger last summer but that hasn't materialized. John Cryan, the chief executive officer of Deutsche Bank, has said the German banking system needed more mergers to become more profitable.