diff --git a/lib/opcodes.py b/lib/opcodes.py
index 44026fdb6f4ccd15d57a387e9fa2849d95ea31ed..4211c717cff9adbbc099f2b44b08c81f9a254890 100644
--- a/lib/opcodes.py
+++ b/lib/opcodes.py
@@ -1234,6 +1234,15 @@ class OpTestDummy(OpCode):
     ]
 
 
-OP_MAPPING = dict([(v.OP_ID, v) for v in globals().values()
-                   if (isinstance(v, type) and issubclass(v, OpCode) and
-                       hasattr(v, "OP_ID"))])
+def _GetOpList():
+  """Returns list of all defined opcodes.
+
+  Does not eliminate duplicates by C{OP_ID}.
+
+  """
+  return [v for v in globals().values()
+          if (isinstance(v, type) and issubclass(v, OpCode) and
+              hasattr(v, "OP_ID"))]
+
+
+OP_MAPPING = dict((v.OP_ID, v) for v in _GetOpList())
diff --git a/test/ganeti.opcodes_unittest.py b/test/ganeti.opcodes_unittest.py
index 5269fc846a0df9bfa7f74679f9cba6a4dd5d0ac7..6be101dd0254849fb9fd0672cc5b14321f16768e 100755
--- a/test/ganeti.opcodes_unittest.py
+++ b/test/ganeti.opcodes_unittest.py
@@ -41,6 +41,7 @@ class TestOpcodes(unittest.TestCase):
 
     for cls in opcodes.OP_MAPPING.values():
       self.assert_(cls.OP_ID.startswith("OP_"))
+      self.assert_(len(cls.OP_ID) > 3)
       self.assertEqual(cls.OP_ID, cls.OP_ID.upper())
 
       self.assertRaises(TypeError, cls, unsupported_parameter="some value")
@@ -84,6 +85,11 @@ class TestOpcodes(unittest.TestCase):
     else:
       self.assertEqual("OP_%s" % summary, op.OP_ID)
 
+  def testOpId(self):
+    self.assertFalse(utils.FindDuplicates(cls.OP_ID
+                                          for cls in opcodes._GetOpList()))
+    self.assertEqual(len(opcodes._GetOpList()), len(opcodes.OP_MAPPING))
+
   def testParams(self):
     supported_by_all = set(["debug_level", "dry_run", "priority"])