diff --git a/src/torchio/transforms/augmentation/intensity/random_motion.py b/src/torchio/transforms/augmentation/intensity/random_motion.py
index 3abea195..f00828da 100644
--- a/src/torchio/transforms/augmentation/intensity/random_motion.py
+++ b/src/torchio/transforms/augmentation/intensity/random_motion.py
@@ -166,6 +166,7 @@ def __init__(
         self.times = times
         self.image_interpolation = image_interpolation
         self.args_names = [
+            'axis',
             'degrees',
             'translation',
             'times',