diff --git a/pkgs/development/interpreters/python/mk-python-derivation.nix b/pkgs/development/interpreters/python/mk-python-derivation.nix
index c85a59390558..670c870f1077 100644
--- a/pkgs/development/interpreters/python/mk-python-derivation.nix
+++ b/pkgs/development/interpreters/python/mk-python-derivation.nix
@@ -53,7 +53,9 @@
 , disabled ? false
 
 # Raise an error if two packages are installed with the same name
-, catchConflicts ? true
+# TODO: For cross we probably need a different PYTHONPATH, or not
+# add the runtime deps until after buildPhase.
+, catchConflicts ? (python.stdenv.hostPlatform == python.stdenv.buildPlatform)
 
 # Additional arguments to pass to the makeWrapper function, which wraps
 # generated binaries.