diff --git a/sleekxmpp/xmlstream/matcher/xmlmask.py b/sleekxmpp/xmlstream/matcher/xmlmask.py
index cb202448..56f728e1 100644
--- a/sleekxmpp/xmlstream/matcher/xmlmask.py
+++ b/sleekxmpp/xmlstream/matcher/xmlmask.py
@@ -37,11 +37,11 @@ class MatchXMLMask(MatcherBase):
                      object or XML string to use as a mask.
     """
 
-    def __init__(self, criteria):
+    def __init__(self, criteria, default_ns='jabber:client'):
         MatcherBase.__init__(self, criteria)
         if isinstance(criteria, str):
             self._criteria = ET.fromstring(self._criteria)
-        self.default_ns = 'jabber:client'
+        self.default_ns = default_ns
 
     def setDefaultNS(self, ns):
         """Set the default namespace to use during comparisons.
diff --git a/sleekxmpp/xmlstream/xmlstream.py b/sleekxmpp/xmlstream/xmlstream.py
index 1c0b84b9..55074932 100644
--- a/sleekxmpp/xmlstream/xmlstream.py
+++ b/sleekxmpp/xmlstream/xmlstream.py
@@ -1017,8 +1017,12 @@ class XMLStream(object):
 
         if name is None:
             name = 'add_handler_%s' % self.new_id()
-        self.register_handler(XMLCallback(name, MatchXMLMask(mask), pointer,
-                                         once=disposable, instream=instream))
+        self.register_handler(
+                XMLCallback(name,
+                    MatchXMLMask(mask, self.default_ns),
+                    pointer,
+                    once=disposable,
+                    instream=instream))
 
     def register_handler(self, handler, before=None, after=None):
         """Add a stream event handler that will be executed when a matching