diff --git a/guix/scripts/system.scm b/guix/scripts/system.scm
index 55e9b8ba30..067bf999f1 100644
--- a/guix/scripts/system.scm
+++ b/guix/scripts/system.scm
@@ -897,7 +897,7 @@ (define* (export-extension-graph os port
          (system   (find (lambda (service)
                            (eq? (service-kind service) system-service-type))
                          services)))
-    (export-graph (list system) (current-output-port)
+    (export-graph (list system) port
                   #:backend backend
                   #:node-type (service-node-type services)
                   #:reverse-edges? #t)))
@@ -913,7 +913,7 @@ (define* (export-shepherd-graph os port
          (sinks     (filter (lambda (service)
                               (null? (shepherd-service-requirement service)))
                             shepherds)))
-    (export-graph sinks (current-output-port)
+    (export-graph sinks port
                   #:backend backend
                   #:node-type (shepherd-service-node-type shepherds)
                   #:reverse-edges? #t)))