diff --git a/src/documents/serialisers.py b/src/documents/serialisers.py
index 155030a68..1f33b957c 100644
--- a/src/documents/serialisers.py
+++ b/src/documents/serialisers.py
@@ -236,6 +236,15 @@ class BulkEditSerializer(serializers.Serializer):
             raise serializers.ValidationError(
                 f"Some documents in {name} don't exist or were specified twice.")
 
+    def _validate_tag_id_list(self, tags, name="tags"):
+        if not type(tags) == list:
+            raise serializers.ValidationError(f"{name} must be a list")
+        if not all([type(i) == int for i in tags]):
+            raise serializers.ValidationError(f"{name} must be a list of integers")
+        count = Tag.objects.filter(id__in=tags).count()
+        if not count == len(tags):
+            raise serializers.ValidationError(
+                f"Some tags in {name} don't exist or were specified twice.")
 
     def validate_documents(self, documents):
         self._validate_document_id_list(documents)
@@ -296,12 +305,12 @@ class BulkEditSerializer(serializers.Serializer):
 
     def _validate_parameters_modify_tags(self, parameters):
         if "add_tags" in parameters:
-            self._validate_document_id_list(parameters['add_tags'], "add_tags")
+            self._validate_tag_id_list(parameters['add_tags'], "add_tags")
         else:
             raise serializers.ValidationError("add_tags not specified")
 
         if "remove_tags" in parameters:
-            self._validate_document_id_list(parameters['remove_tags'], "remove_tags")
+            self._validate_tag_id_list(parameters['remove_tags'], "remove_tags")
         else:
             raise serializers.ValidationError("remove_tags not specified")