diff --git a/ndcube/tests/test_ndcube.py b/ndcube/tests/test_ndcube.py
index 1eb7f4988..d6b6d931d 100644
--- a/ndcube/tests/test_ndcube.py
+++ b/ndcube/tests/test_ndcube.py
@@ -663,6 +663,8 @@ def test_slicing_error(test_input):
         test_input[None]
     with pytest.raises(IndexError):
         test_input[0, None]
+    with pytest.raises(NotImplementedError):
+        test_input[[0, 1]]
 
 
 @pytest.mark.parametrize("test_input,expected", [
diff --git a/ndcube/utils/wcs.py b/ndcube/utils/wcs.py
index d48ebaeaa..ed4973f8e 100644
--- a/ndcube/utils/wcs.py
+++ b/ndcube/utils/wcs.py
@@ -206,6 +206,8 @@ def _wcs_slicer(wcs, missing_axis, item):
             for i, it in enumerate(item_checked):
                 if isinstance(it, int):
                     missing_axis[i] = True
+    else:
+        raise NotImplementedError("Slicing FITS-WCS by {0} not supported.".format(type(item)))
     # returning the reverse list of missing axis as in the item here was reverse of
     # what was inputed so we had a reverse missing_axis.
     return new_wcs, missing_axis[::-1]