The warnings come as the Bundesbank and Germany's BaFin regulator call banks to discuss the results of stress tests. Some German public banks may be forced to accept state aid on harsh terms to beef up asset ratios. BaFin said last year that German banks may face write-downs of €800bn (£653bn). The EU is conducting tests on up to 100 European banks to help restore confidence in frozen inter-bank markets. The results will be released in late July.