diff --git a/swh/deposit/api/common.py b/swh/deposit/api/common.py
--- a/swh/deposit/api/common.py
+++ b/swh/deposit/api/common.py
@@ -75,7 +75,11 @@
 )
 from ..models import DepositClient, DepositCollection, DepositRequest
 from ..parsers import parse_xml
-from ..utils import extended_swhid_from_qualified, parse_swh_reference
+from ..utils import (
+    extended_swhid_from_qualified,
+    parse_swh_deposit_origin,
+    parse_swh_reference,
+)
 
 ACCEPT_PACKAGINGS = ["http://purl.org/net/sword/package/SimpleZip"]
 ACCEPT_ARCHIVE_CONTENT_TYPES = ["application/zip", "application/x-tar"]
@@ -911,14 +915,9 @@
         )
 
     def _set_deposit_origin_from_metadata(self, deposit, metadata, headers):
-        create_origin = metadata.find(
-            "swh:deposit/swh:create_origin/swh:origin", namespaces=NAMESPACES
-        )
-        add_to_origin = metadata.find(
-            "swh:deposit/swh:add_to_origin/swh:origin", namespaces=NAMESPACES
-        )
+        (create_origin, add_to_origin) = parse_swh_deposit_origin(metadata)
 
-        if create_origin is not None and add_to_origin is not None:
+        if create_origin and add_to_origin:
             raise DepositError(
                 BAD_REQUEST,
                 "<swh:create_origin> and <swh:add_to_origin> are mutually exclusive, "
@@ -926,13 +925,13 @@
                 "origin.",
             )
 
-        if create_origin is not None:
-            origin_url = create_origin.attrib["url"]
+        if create_origin:
+            origin_url = create_origin
             check_client_origin(deposit.client, origin_url)
             deposit.origin_url = origin_url
 
-        if add_to_origin is not None:
-            origin_url = add_to_origin.attrib["url"]
+        if add_to_origin:
+            origin_url = add_to_origin
             check_client_origin(deposit.client, origin_url)
             deposit.parent = (
                 Deposit.objects.filter(
diff --git a/swh/deposit/cli/client.py b/swh/deposit/cli/client.py
--- a/swh/deposit/cli/client.py
+++ b/swh/deposit/cli/client.py
@@ -278,23 +278,25 @@
     if metadata:
         from xml.etree import ElementTree
 
-        from swh.deposit.utils import parse_swh_metadata_provenance, parse_xml
-
-        metadata_raw = open(metadata, "r").read()
-        metadata_dict = parse_xml(metadata_raw)
-        metadata_swh = metadata_dict.get("swh:deposit", {})
-        if (
-            "swh:create_origin" not in metadata_swh
-            and "swh:add_to_origin" not in metadata_swh
-        ):
+        from swh.deposit.utils import (
+            parse_swh_deposit_origin,
+            parse_swh_metadata_provenance,
+        )
+
+        metadata_tree = ElementTree.fromstring(open(metadata).read())
+        (create_origin, add_to_origin) = parse_swh_deposit_origin(metadata_tree)
+        if create_origin and add_to_origin:
+            logger.error(
+                "The metadata file provided must not contain both "
+                '"<swh:create_origin>" and "<swh:add_to_origin>" tags',
+            )
+        elif not create_origin and not add_to_origin:
             logger.warning(
                 "The metadata file provided should contain "
                 '"<swh:create_origin>" or "<swh:add_to_origin>" tag',
             )
 
-        meta_prov_url = parse_swh_metadata_provenance(
-            ElementTree.fromstring(metadata_raw)
-        )
+        meta_prov_url = parse_swh_metadata_provenance(metadata_tree)
 
         if not meta_prov_url:
             logger.warning(
diff --git a/swh/deposit/utils.py b/swh/deposit/utils.py
--- a/swh/deposit/utils.py
+++ b/swh/deposit/utils.py
@@ -4,7 +4,7 @@
 # See top-level LICENSE file for more information
 
 import logging
-from typing import Any, Dict, Optional, Union
+from typing import Any, Dict, Optional, Tuple, Union
 from xml.etree import ElementTree
 
 import iso8601
@@ -109,7 +109,7 @@
 
          <swh:deposit>
            <swh:metadata-provenance>
-             <schema:url>https://url.org/metadata/url</schema:url>
+             <schema:url>https://example.org/metadata/url</schema:url>
            </swh:metadata-provenance>
          </swh:deposit>
 
@@ -131,11 +131,49 @@
     return None
 
 
+def parse_swh_deposit_origin(
+    metadata: ElementTree.Element,
+) -> Tuple[Optional[str], Optional[str]]:
+    """Parses <swh:add_to_origin> and <swh:create_origin> from metadata document,
+    if any.
+
+    .. code-block:: xml
+
+       <swh:deposit>
+         <swh:create_origin>
+           <swh:origin url='https://example.org/repo/software123/'/>
+         </swh:reference>
+       </swh:deposit>
+
+    .. code-block:: xml
+
+       <swh:deposit>
+         <swh:add_to_origin>
+           <swh:origin url='https://example.org/repo/software123/'/>
+         </swh:add_to_origin>
+       </swh:deposit>
+
+    Returns:
+        tuple of (origin_to_create, origin_to_add). If both are non-None, this
+        should typically be an error raised to the user.
+    """
+    create_origin = metadata.find(
+        "swh:deposit/swh:create_origin/swh:origin", namespaces=NAMESPACES
+    )
+    add_to_origin = metadata.find(
+        "swh:deposit/swh:add_to_origin/swh:origin", namespaces=NAMESPACES
+    )
+
+    return (
+        None if create_origin is None else create_origin.attrib["url"],
+        None if add_to_origin is None else add_to_origin.attrib["url"],
+    )
+
+
 def parse_swh_reference(
     metadata: ElementTree.Element,
 ) -> Optional[Union[QualifiedSWHID, str]]:
-    """Parse swh reference within the metadata dict (or origin) reference if found,
-    None otherwise.
+    """Parse <swh:reference> within the metadata document, if any.
 
     .. code-block:: xml