diff --git includes/menu.inc includes/menu.inc
index a3121c7..246d076 100644
--- includes/menu.inc
+++ includes/menu.inc
@@ -618,6 +618,13 @@ function _menu_check_access(&$item, $map) {
     elseif (function_exists($callback)) {
       $item['access'] = call_user_func_array($callback, $arguments);
     }
+    else {
+      watchdog('menu.inc',
+        'Undefined access callback function :callback in router_item :item',
+        array(':callback' => $callback, ':item' => var_export($item,1)),
+        WATCHDOG_WARNING);
+      $item['access'] = FALSE;
+    }
   }
 }