diff --git a/libguile/strports.c b/libguile/strports.c
index 19e6e0f9a..af1928ce3 100644
--- a/libguile/strports.c
+++ b/libguile/strports.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1995,1996,1998,1999,2000,2001 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1998,1999,2000,2001,2005 Free Software Foundation, Inc.
  * 
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -133,7 +133,7 @@ st_flush (SCM port)
 
   if (pt->write_pos == pt->write_end)
     {
-      st_resize_port (pt, pt->write_buf_size + SCM_WRITE_BLOCK);
+      st_resize_port (pt, pt->write_buf_size * 3 / 2 + SCM_WRITE_BLOCK);
     }
   pt->read_pos = pt->write_pos;
   if (pt->read_pos > pt->read_end)