The formal request was made in a letter sent late last year, shortly before Hamburg-based HSH Nordbank said it would raise loan loss provisions to match increased levels of default on ship loans.

Germany's 12 largest banks had exposure of around 98 billion euros ($129.2 billion) to the stricken shipping sector in mid-2012, statistics based on mid-2012 figures showed.

Dirk Mueller-Tronnier, country leader for banking at Ernst & Young Germany said, "BaFin asked companies and auditors to put particular emphasis on shipping loans as they prepare full-year reports."

The three other sources asked not to be identified.

Aside from HSH and NordLB, large banks with exposure to the shipping sector include Commerzbank and Deutsche Bank.

Center>Copyright Reuters, 2013