diff --git a/src/pyodide/internal/setupPackages.ts b/src/pyodide/internal/setupPackages.ts
index 775b2150630..0d20566fc9e 100644
--- a/src/pyodide/internal/setupPackages.ts
+++ b/src/pyodide/internal/setupPackages.ts
@@ -131,6 +131,11 @@ class SitePackagesDir {
  * TODO(later): This needs to be removed when external package loading is enabled.
  */
 export function buildSitePackages(requirements: Set<string>): SitePackagesDir {
+  if (EmbeddedPackagesTarReader.read === undefined) {
+    // Package retrieval is enabled, so the embedded tar reader isn't initialised.
+    return new SitePackagesDir();
+  }
+
   const [bigTarInfo, bigTarSoFiles] = parseTarInfo(EmbeddedPackagesTarReader);
 
   let requirementsInBigBundle = new Set([...STDLIB_PACKAGES]);
diff --git a/src/workerd/server/workerd-api.c++ b/src/workerd/server/workerd-api.c++
index b11b81f537a..2ea923053a9 100644
--- a/src/workerd/server/workerd-api.c++
+++ b/src/workerd/server/workerd-api.c++
@@ -572,10 +572,14 @@ void WorkerdApi::compileModules(jsg::Lock& lockParam,
           makePyodideMetadataReader(conf, impl->pythonConfig), jsg::ModuleRegistry::Type::INTERNAL);
 
       // Inject packages tar file
-      // TODO(later): This shouldn't exist once featureFlags.getPythonExternalPackages() is true.
-      modules->addBuiltinModule("pyodide-internal:packages_tar_reader",
-          jsg::alloc<ReadOnlyBuffer>(PYODIDE_PACKAGES_TAR.get()),
-          workerd::jsg::ModuleRegistry::Type::INTERNAL);
+      if (featureFlags.getPythonExternalPackages()) {
+        modules->addBuiltinModule("pyodide-internal:packages_tar_reader", "export default { }"_kj,
+            workerd::jsg::ModuleRegistry::Type::INTERNAL, {});
+      } else {
+        modules->addBuiltinModule("pyodide-internal:packages_tar_reader",
+            jsg::alloc<ReadOnlyBuffer>(PYODIDE_PACKAGES_TAR.get()),
+            workerd::jsg::ModuleRegistry::Type::INTERNAL);
+      }
 
       // Inject artifact bundler.
       modules->addBuiltinModule("pyodide-internal:artifacts",