diff --git a/osmclient/scripts/osm.py b/osmclient/scripts/osm.py
index 23f258e92fe592da13861bd9b71224b7c5821615..15b38e47f5929420394dc4354afd4d09f991645c 100755
--- a/osmclient/scripts/osm.py
+++ b/osmclient/scripts/osm.py
@@ -1073,6 +1073,7 @@ def vcs_list(ctx):
 def ns_action(ctx,
               ns_name,
               vnf_name,
+              action_name,
               params):
     '''executes an action/primitive over a NS instance