diff --git a/py_gen/templates/_pack.py b/py_gen/templates/_pack.py
index e853833..0c208f7 100644
--- a/py_gen/templates/_pack.py
+++ b/py_gen/templates/_pack.py
@@ -57,3 +57,6 @@
         length = sum([len(x) for x in packed])
         packed[${length_member_index}] = ${length_member.oftype.gen_pack_expr('length')}
 :: #endif
+:: if ofclass.name == 'of_match_v3':
+        packed.append('\x00' * ((length + 7)/8*8 - length))
+:: #endif