diff --git a/batchgenerators/augmentations/utils.py b/batchgenerators/augmentations/utils.py
index f8aac77..3212b0b 100755
--- a/batchgenerators/augmentations/utils.py
+++ b/batchgenerators/augmentations/utils.py
@@ -591,11 +591,12 @@ def resize_segmentation(segmentation, new_shape, order=3):
     :return:
     '''
     tpe = segmentation.dtype
-    unique_labels = np.unique(segmentation)
+    
     assert len(segmentation.shape) == len(new_shape), "new shape must have same dimensionality as segmentation"
     if order == 0:
         return resize(segmentation.astype(float), new_shape, order, mode="edge", clip=True, anti_aliasing=False).astype(tpe)
     else:
+        unique_labels = np.unique(segmentation)
         reshaped = np.zeros(new_shape, dtype=segmentation.dtype)
 
         for i, c in enumerate(unique_labels):