diff --git a/src/core/ddsi/src/q_init.c b/src/core/ddsi/src/q_init.c
index 926a120..4c453d9 100644
--- a/src/core/ddsi/src/q_init.c
+++ b/src/core/ddsi/src/q_init.c
@@ -1125,8 +1125,11 @@ int rtps_init (void)
     }
   }
 
-  nn_xpack_sendq_init();
-  nn_xpack_sendq_start();
+  if (config.xpack_send_async)
+  {
+    nn_xpack_sendq_init();
+    nn_xpack_sendq_start();
+  }
 
 #ifdef DDSI_INCLUDE_NETWORK_CHANNELS
   /* Create a delivery queue and start tev for each channel */
@@ -1413,8 +1416,11 @@ void rtps_term (void)
 
   xeventq_free (gv.xevents);
 
-  nn_xpack_sendq_stop();
-  nn_xpack_sendq_fini();
+  if (config.xpack_send_async)
+  {
+    nn_xpack_sendq_stop();
+    nn_xpack_sendq_fini();
+  }
 
 #ifdef DDSI_INCLUDE_NETWORK_CHANNELS
   chptr = config.channels;
diff --git a/src/core/ddsi/src/q_xmsg.c b/src/core/ddsi/src/q_xmsg.c
index 0141b67..1643cb8 100644
--- a/src/core/ddsi/src/q_xmsg.c
+++ b/src/core/ddsi/src/q_xmsg.c
@@ -1236,6 +1236,10 @@ struct nn_xpack * nn_xpack_new (ddsi_tran_conn_t conn, uint32_t bw_limit, bool a
   const nn_vendorid_t myvendorid = MY_VENDOR_ID;
   struct nn_xpack *xp;
 
+  /* Disallow setting async_mode if not configured to enable async mode: this way we
+     can avoid starting the async send thread altogether */
+  assert (!async_mode || config.xpack_send_async);
+
   xp = os_malloc (sizeof (*xp));
   memset (xp, 0, sizeof (*xp));
   xp->async_mode = async_mode;