diff --git a/etc/spack/defaults/packages.yaml b/etc/spack/defaults/packages.yaml
index f23d55ffb9f..f340cdfeafc 100644
--- a/etc/spack/defaults/packages.yaml
+++ b/etc/spack/defaults/packages.yaml
@@ -92,6 +92,8 @@ packages:
     buildable: false
   hpcx-mpi:
     buildable: false
+  iconv:
+    prefer: [libiconv]
   mpt:
     buildable: false
   spectrum-mpi: