diff --git a/monai/inferers/merger.py b/monai/inferers/merger.py
index 583cf68a70..e10ad4d406 100644
--- a/monai/inferers/merger.py
+++ b/monai/inferers/merger.py
@@ -249,13 +249,13 @@ def __init__(
         self.store = store
         if version_geq(get_package_version("zarr"), "3.0.0"):
             if value_store is None:
-                with TemporaryDirectory() as tmpdir:
-                    self.value_store = zarr.storage.LocalStore(tmpdir)
+                tmpdir = TemporaryDirectory()
+                self.value_store = zarr.storage.LocalStore(tmpdir.name)
             else:
                 self.value_store = value_store
             if count_store is None:
-                with TemporaryDirectory() as tmpdir:
-                    self.count_store = zarr.storage.LocalStore(tmpdir)
+                tmpdir = TemporaryDirectory()
+                self.count_store = zarr.storage.LocalStore(tmpdir.name)
             else:
                 self.count_store = count_store
         else:
diff --git a/tests/test_zarr_avg_merger.py b/tests/test_zarr_avg_merger.py
index dba046f9ed..3c89e4fb03 100644
--- a/tests/test_zarr_avg_merger.py
+++ b/tests/test_zarr_avg_merger.py
@@ -287,19 +287,16 @@ class ZarrAvgMergerTests(unittest.TestCase):
         ]
     )
     def test_zarr_avg_merger_patches(self, arguments, patch_locations, expected):
+        codec_reg = numcodecs.registry.codec_registry
         if "compressor" in arguments:
             if arguments["compressor"] != "default":
-                arguments["compressor"] = numcodecs.registry.codec_registry[arguments["compressor"].lower()]()
+                arguments["compressor"] = codec_reg[arguments["compressor"].lower()]()
         if "value_compressor" in arguments:
             if arguments["value_compressor"] != "default":
-                arguments["value_compressor"] = numcodecs.registry.codec_registry[
-                    arguments["value_compressor"].lower()
-                ]()
+                arguments["value_compressor"] = codec_reg[arguments["value_compressor"].lower()]()
         if "count_compressor" in arguments:
             if arguments["count_compressor"] != "default":
-                arguments["count_compressor"] = numcodecs.registry.codec_registry[
-                    arguments["count_compressor"].lower()
-                ]()
+                arguments["count_compressor"] = codec_reg[arguments["count_compressor"].lower()]()
         merger = ZarrAvgMerger(**arguments)
         for pl in patch_locations:
             merger.aggregate(pl[0], pl[1])