diff --git a/moto/organizations/models.py b/moto/organizations/models.py
index 6fa525113069..8ff334ff3ee6 100644
--- a/moto/organizations/models.py
+++ b/moto/organizations/models.py
@@ -538,9 +538,9 @@ def list_organizational_units_for_parent(
         ]
 
     def create_account(self, **kwargs: Any) -> Dict[str, Any]:
-        if (
-            self.org is None
-            or self.account_id not in organizations_backends.master_accounts
+        if self.org is None or (
+            self.account_id != self.org.master_account_id
+            and self.account_id not in organizations_backends.master_accounts
         ):
             raise AWSOrganizationsNotInUseException
 
@@ -554,9 +554,9 @@ def create_account(self, **kwargs: Any) -> Dict[str, Any]:
         return new_account.create_account_status
 
     def close_account(self, **kwargs: Any) -> None:
-        if (
-            self.org is None
-            or self.account_id not in organizations_backends.master_accounts
+        if self.org is None or (
+            self.account_id != self.org.master_account_id
+            and self.account_id not in organizations_backends.master_accounts
         ):
             raise AWSOrganizationsNotInUseException