diff --git a/monai/bundle/scripts.py b/monai/bundle/scripts.py
index 052b5ab763..948f1ba18b 100644
--- a/monai/bundle/scripts.py
+++ b/monai/bundle/scripts.py
@@ -864,8 +864,8 @@ def init_bundle(
     ckpt_file: Optional[PathLike] = None,
     network: Optional[torch.nn.Module] = None,
     dataset_license: bool = False,
-    metadata_str: Union[Dict, str] = DEFAULT_METADATA,
-    inference_str: Union[Dict, str] = DEFAULT_INFERENCE,
+    metadata_str: Union[Dict, str] = None,
+    inference_str: Union[Dict, str] = None,
 ):
     """
     Initialise a new bundle directory with some default configuration files and optionally network weights.
@@ -883,6 +883,10 @@ def init_bundle(
         dataset_license: if `True`, a default license file called "data_license.txt" will be produced. This
             file is required if there are any license conditions stated for data your bundle uses.
     """
+    if metadata_str is None:
+        metadata_str = DEFAULT_METADATA
+    if inference_str is None:
+        inference_str = DEFAULT_INFERENCE
 
     bundle_dir = Path(bundle_dir).absolute()