diff --git a/repos/c2sm/packages/icon/package.py b/repos/c2sm/packages/icon/package.py
index d451a815d2..83289b3ea6 100755
--- a/repos/c2sm/packages/icon/package.py
+++ b/repos/c2sm/packages/icon/package.py
@@ -456,7 +456,7 @@ def configure_args(self):
             if self.spec.variants['gpu'].value == 'openacc+cuda':
                 config_vars['FCFLAGS'].extend([
                     '-acc=verystrict', '-Minfo=accel,inline',
-                    '-gpu=cc{0}'.format(
+                    '-gpu=cc{0},fastmath'.format(
                         self.spec.variants['cuda_arch'].value[0])
                 ])
         elif self.compiler.name == 'cce':