diff --git a/src/modules/dialog/dialog.c b/src/modules/dialog/dialog.c
index ce69fc94ca0..497176a7607 100644
--- a/src/modules/dialog/dialog.c
+++ b/src/modules/dialog/dialog.c
@@ -515,8 +515,8 @@ static int mod_init(void)
 		return -1;
 
 	/* param checkings */
-	if (dlg_flag>MAX_FLAG) {
-		LM_ERR("invalid dlg flag %d!!\n",dlg_flag);
+	if (dlg_flag!=-1 && dlg_flag>MAX_FLAG) {
+		LM_ERR("invalid dlg flag %d!!\n", dlg_flag);
 		return -1;
 	}
 
diff --git a/src/modules/dialog/dlg_handlers.c b/src/modules/dialog/dlg_handlers.c
index 96406bde356..c80ca7d59f6 100644
--- a/src/modules/dialog/dlg_handlers.c
+++ b/src/modules/dialog/dlg_handlers.c
@@ -761,8 +761,10 @@ void dlg_onreq(struct cell* t, int type, struct tmcb_params *param)
 		}
 	}
 	if (dlg==NULL) {
-		if((req->flags&dlg_flag_mask)!=dlg_flag_mask)
+		if((dlg_flag_mask==0) || (req->flags&dlg_flag_mask)!=dlg_flag_mask) {
+			LM_DBG("flag not set for creating a new dialog\n");
 			return;
+		}
 		LM_DBG("dialog creation on config flag\n");
 		dlg_new_dialog(req, t, 1);
 		dlg = dlg_get_ctx_dialog();