diff --git a/packaging/source/buildpackage.sh b/packaging/source/buildpackage.sh
index 62a05412f2..457a4e2460 100755
--- a/packaging/source/buildpackage.sh
+++ b/packaging/source/buildpackage.sh
@@ -15,5 +15,12 @@ SRCDIR="$(pwd)/../.."
 
 pushd "${SRCDIR}" > /dev/null || exit 1
 make version VERSION="${TAG}"
-git ls-tree HEAD --name-only -r -z | xargs -0 tar cvjf "${OUTPUTDIR}/OpenRA-${TAG}-source.tar.bz2"
+
+# The output from `git ls-tree` is too long to fit in a single command (overflows MAX_ARG_STRLEN)
+# so `xargs` will automatically split the input across multiple `tar` commands.
+# Use the amend flag (r) to prevent each call erasing the output from earlier calls.
+rm "${OUTPUTDIR}/OpenRA-${TAG}-source.tar"
+git ls-tree HEAD --name-only -r -z | xargs -0 tar vrf "${OUTPUTDIR}/OpenRA-${TAG}-source.tar"
+bzip2 "${OUTPUTDIR}/OpenRA-${TAG}-source.tar"
+
 popd > /dev/null || exit 1