diff --git a/tests/codes_compare_keys.cc b/tests/codes_compare_keys.cc
index a758c8810..80f0c383c 100644
--- a/tests/codes_compare_keys.cc
+++ b/tests/codes_compare_keys.cc
@@ -17,13 +17,19 @@ int main(int argc, char* argv[])
     grib_handle* h1 = NULL;
     grib_handle* h2 = NULL;
     int err       = 0;
-    size_t count  = 0;
+    size_t num_diffs = 0, i = 0;
+    char** list_provided_keys = NULL;
 
-    Assert(argc == 3);
     f1 = fopen(argv[1], "rb");
     f2 = fopen(argv[2], "rb");
     Assert(f1 && f2);
 
+    if (argc == 4) {
+        // List of keys is also given on the command line
+        char* input = argv[3];
+        list_provided_keys = string_split(input, ",");
+    }
+
     while ((h1 = grib_handle_new_from_file(0, f1, &err)) != NULL && (h2 = grib_handle_new_from_file(0, f2, &err)) != NULL) {
         grib_keys_iterator* kiter = NULL;
 
@@ -36,10 +42,11 @@ int main(int argc, char* argv[])
         while (grib_keys_iterator_next(kiter)) {
             const char* name = grib_keys_iterator_get_name(kiter);
             Assert(name);
+            //printf(".... %s \n",name);
             err = codes_compare_key(h1, h2, name, 0);
             if (err) {
                 fprintf(stderr, "key: %s  (%s)\n", name, grib_get_error_message(err));
-                ++count;
+                ++num_diffs;
             }
         }
 
@@ -49,14 +56,33 @@ int main(int argc, char* argv[])
         codes_compare_key(h1, h2, "paramId", 0);    // concept
         codes_compare_key(h1, h2, "identifier", 0); // ascii
 
+        if (list_provided_keys) {
+            for (i = 0; list_provided_keys[i] != NULL; ++i) {
+                const char* pkey = list_provided_keys[i];
+                printf("Comparing provided key %s ...\n", list_provided_keys[i]);
+                err = codes_compare_key(h1, h2, pkey, 0);
+                if (err) {
+                    fprintf(stderr, "key: %s  (%s)\n", pkey, grib_get_error_message(err));
+                    ++num_diffs;
+                }
+            }
+        }
+
         grib_keys_iterator_delete(kiter);
         grib_handle_delete(h1);
         grib_handle_delete(h2);
     }
+
     fclose(f1);
     fclose(f2);
-    if (count > 0) {
-        fprintf(stderr, "\nComparison failed: %zu differences\n", count);
+
+    if (list_provided_keys) {
+        for (i = 0; list_provided_keys[i] != NULL; ++i) free(list_provided_keys[i]);
+        free(list_provided_keys);
+    }
+
+    if (num_diffs > 0) {
+        fprintf(stderr, "\nComparison failed: %zu differences\n", num_diffs);
         return 1;
     }
     return 0;
diff --git a/tests/codes_compare_keys.sh b/tests/codes_compare_keys.sh
index c5918f769..39a95f304 100755
--- a/tests/codes_compare_keys.sh
+++ b/tests/codes_compare_keys.sh
@@ -63,5 +63,16 @@ EOF
 
 diff $tempRef $tempLog
 
+# Local definitions
+# ----------------------
+sample1=$ECCODES_SAMPLES_PATH/GRIB1.tmpl
+tempGribA=temp.${label}.A.grib
+tempGribB=temp.${label}.B.grib
+${tools_dir}/grib_set -s localDefinitionNumber=16,verifyingMonth=11 $sample1 $tempGribA
+${tools_dir}/grib_set -s localDefinitionNumber=16,verifyingMonth=11 $sample1 $tempGribB
+${test_dir}/codes_compare_keys $tempGribA $tempGribB endOfInterval
+rm -f $tempGribA $tempGribB
+
+
 # Clean up
 rm -f $tempLog $tempRef $tempGrib