diff --git a/python/idsse_common/idsse/common/aws_utils.py b/python/idsse_common/idsse/common/aws_utils.py
index 2646fc4..e54af6d 100644
--- a/python/idsse_common/idsse/common/aws_utils.py
+++ b/python/idsse_common/idsse/common/aws_utils.py
@@ -94,9 +94,9 @@ def aws_cp(self,
 
             # if concurrency and/or chunk_size options were provided, append to s5cmd before paths
             if concurrency:
-                commands += ['--concurrency', concurrency]
+                commands += ['--concurrency', str(concurrency)]
             if chunk_size:
-                commands += ['--part_size', chunk_size]
+                commands += ['--part-size', str(chunk_size)]
             commands += [path, dest]  # finish the command list with the src and destination
 
             exec_cmd(commands)