diff --git a/synapse/notifier.py b/synapse/notifier.py
index 7eeba6d28..f9fcc0ca2 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -550,3 +550,9 @@ class Notifier(object):
                 break
 
         defer.returnValue(result)
+
+    def wait_once_for_replication(self):
+        """Returns a deferred which resolves when there is new data for
+        replication to handle.
+        """
+        return self.replication_deferred.observe()