diff --git a/gitlab/v4/objects.py b/gitlab/v4/objects.py
index bc45bf1a9..9e9269d7b 100644
--- a/gitlab/v4/objects.py
+++ b/gitlab/v4/objects.py
@@ -3251,7 +3251,7 @@ def merge(
         if merge_when_pipeline_succeeds:
             data["merge_when_pipeline_succeeds"] = True
 
-        server_data = self.manager.gitlab.http_put(path, post_data=data, **kwargs)
+        server_data = self.manager.gitlab.http_put(path, query_data=data, **kwargs)
         self._update_attrs(server_data)