diff --git a/Tools/NumDiff.py b/Tools/NumDiff.py
index a8f20a5444..608cc51cc6 100644
--- a/Tools/NumDiff.py
+++ b/Tools/NumDiff.py
@@ -119,7 +119,11 @@ def takeImportantThings_python(ename, aname, dname):
   idxAux = 0
 
   absErrorUB = 1e-09
+  if 'ABSOLUTE_ERROR' in os.environ:
+    absErrorUB = float(os.environ['ABSOLUTE_ERROR'])
   relErrorUB = 1e-05
+  if 'RELATIVE_ERROR' in os.environ:
+    relErrorUB = float(os.environ['RELATIVE_ERROR'])
 
   file3 = open(dname, 'w')
 
diff --git a/copasi/CopasiSE/CMakeLists.txt b/copasi/CopasiSE/CMakeLists.txt
index 9c8b95b4d7..add2e93514 100644
--- a/copasi/CopasiSE/CMakeLists.txt
+++ b/copasi/CopasiSE/CMakeLists.txt
@@ -55,6 +55,8 @@ add_test(NAME CopasiTestsuite
          
 )
 set_tests_properties(CopasiTestsuite PROPERTIES FAIL_REGULAR_EXPRESSION "ifferent")	
+# reduce precision, as the test comparison code uses truncated data
+set_tests_properties(CopasiTestsuite PROPERTIES ENVIRONMENT "ABSOLUTE_ERROR=1e-04;RELATIVE_ERROR=1e-04")	
 
 endif()