diff --git a/mlserver/parallel/registry.py b/mlserver/parallel/registry.py
index 86bd51ce8..55c1109f9 100644
--- a/mlserver/parallel/registry.py
+++ b/mlserver/parallel/registry.py
@@ -130,6 +130,12 @@ def model_initialiser(self, model_settings: ModelSettings) -> MLModel:
             # as normal.
             return model_initialiser(model_settings)
 
+        parameters = model_settings.parameters
+        if not parameters or not parameters.environment_tarball:
+            # If model is not using a custom environment, instantiate the model
+            # as normal.
+            return model_initialiser(model_settings)
+
         # Otherwise, return a dummy model for now and wait for the load_model
         # hook to create the actual thing.
         # This avoids instantiating the model's actual class within the
diff --git a/runtimes/alibi-explain/tests/conftest.py b/runtimes/alibi-explain/tests/conftest.py
index 2bffbe59a..3298272a9 100644
--- a/runtimes/alibi-explain/tests/conftest.py
+++ b/runtimes/alibi-explain/tests/conftest.py
@@ -115,6 +115,7 @@ async def model_registry(
         on_model_load=[inference_pool_registry.load_model],
         on_model_reload=[inference_pool_registry.reload_model],
         on_model_unload=[inference_pool_registry.unload_model],
+        model_initialiser=inference_pool_registry.model_initialiser,
     )
 
     await model_registry.load(custom_runtime_tf_settings)
diff --git a/runtimes/mlflow/tests/rest/conftest.py b/runtimes/mlflow/tests/rest/conftest.py
index 80af20dc4..8a5df840c 100644
--- a/runtimes/mlflow/tests/rest/conftest.py
+++ b/runtimes/mlflow/tests/rest/conftest.py
@@ -71,6 +71,7 @@ async def model_registry(
         on_model_load=[inference_pool_registry.load_model],
         on_model_reload=[inference_pool_registry.reload_model],
         on_model_unload=[inference_pool_registry.unload_model],
+        model_initialiser=inference_pool_registry.model_initialiser,
     )
 
     await model_registry.load(model_settings)
diff --git a/tests/grpc/conftest.py b/tests/grpc/conftest.py
index 7c66a08ab..be4d5c765 100644
--- a/tests/grpc/conftest.py
+++ b/tests/grpc/conftest.py
@@ -37,6 +37,7 @@ async def model_registry(
         on_model_load=[inference_pool_registry.load_model, load_batching],
         on_model_reload=[inference_pool_registry.reload_model],
         on_model_unload=[inference_pool_registry.unload_model],
+        model_initialiser=inference_pool_registry.model_initialiser,
     )
 
     model_name = sum_model_settings.name
diff --git a/tests/rest/conftest.py b/tests/rest/conftest.py
index 4bf8767d6..e31ad5473 100644
--- a/tests/rest/conftest.py
+++ b/tests/rest/conftest.py
@@ -22,6 +22,7 @@ async def model_registry(
         on_model_load=[inference_pool_registry.load_model, load_batching],
         on_model_reload=[inference_pool_registry.reload_model],
         on_model_unload=[inference_pool_registry.unload_model],
+        model_initialiser=inference_pool_registry.model_initialiser,
     )
 
     model_name = sum_model_settings.name