diff --git a/djangorestframework/resources.py b/djangorestframework/resources.py
index 5e350268b..81c2fda79 100644
--- a/djangorestframework/resources.py
+++ b/djangorestframework/resources.py
@@ -309,14 +309,11 @@ class ModelResource(FormResource):
             return None
 
         # Instantiate the ModelForm as appropriate
-        if data is not None or files is not None:
-            if issubclass(form, forms.ModelForm) and hasattr(self.view, 'model_instance'):
-                # Bound to an existing model instance
-                return form(data, files, instance=self.view.model_instance)
-            else:
-                return form(data, files)
+        form_kwargs = {'data': data, 'files': files}
+         # Bound to an existing model instance
+        if issubclass(form, forms.ModelForm) and hasattr(self.view, 'model_instance'): form_kwargs['instance'] = self.view.model_instance
 
-        return form()
+        return form(**form_kwargs)
 
     @property
     def _model_fields_set(self):