diff --git a/neutron/agent/l3/dvr_edge_router.py b/neutron/agent/l3/dvr_edge_router.py
index e7f63f40112..efdf1609e18 100644
--- a/neutron/agent/l3/dvr_edge_router.py
+++ b/neutron/agent/l3/dvr_edge_router.py
@@ -242,3 +242,18 @@ class DvrEdgeRouter(dvr_local_router.DvrLocalRouter):
         with self.snat_iptables_manager.defer_apply():
             self._add_address_scope_mark(
                 self.snat_iptables_manager, ports_scopemark)
+
+    def _delete_stale_external_devices(self, interface_name):
+        if not self.snat_namespace.exists():
+            return
+
+        ns_ip = ip_lib.IPWrapper(namespace=self.snat_namespace.name)
+        for d in ns_ip.get_devices(exclude_loopback=True):
+            if (d.name.startswith(router.EXTERNAL_DEV_PREFIX) and
+                    d.name != interface_name):
+                LOG.debug('Deleting stale external router device: %s', d.name)
+                self.driver.unplug(
+                    d.name,
+                    bridge=self.agent_conf.external_network_bridge,
+                    namespace=self.snat_namespace.name,
+                    prefix=router.EXTERNAL_DEV_PREFIX)
diff --git a/neutron/agent/l3/router_info.py b/neutron/agent/l3/router_info.py
index 7670984e71f..a7fe32de66d 100644
--- a/neutron/agent/l3/router_info.py
+++ b/neutron/agent/l3/router_info.py
@@ -713,6 +713,19 @@ class RouterInfo(object):
     def _gateway_ports_equal(port1, port2):
         return port1 == port2
 
+    def _delete_stale_external_devices(self, interface_name):
+        existing_devices = self._get_existing_devices()
+        stale_devs = [dev for dev in existing_devices
+                      if dev.startswith(EXTERNAL_DEV_PREFIX)
+                      and dev != interface_name]
+        for stale_dev in stale_devs:
+            LOG.debug('Deleting stale external router device: %s', stale_dev)
+            self.agent.pd.remove_gw_interface(self.router['id'])
+            self.driver.unplug(stale_dev,
+                               bridge=self.agent_conf.external_network_bridge,
+                               namespace=self.ns_name,
+                               prefix=EXTERNAL_DEV_PREFIX)
+
     def _process_external_gateway(self, ex_gw_port):
         # TODO(Carl) Refactor to clarify roles of ex_gw_port vs self.ex_gw_port
         ex_gw_port_id = (ex_gw_port and ex_gw_port['id'] or
@@ -736,17 +749,7 @@ class RouterInfo(object):
                 interface_name = self.get_internal_device_name(p['id'])
                 self.gateway_redirect_cleanup(interface_name)
 
-        existing_devices = self._get_existing_devices()
-        stale_devs = [dev for dev in existing_devices
-                      if dev.startswith(EXTERNAL_DEV_PREFIX)
-                      and dev != interface_name]
-        for stale_dev in stale_devs:
-            LOG.debug('Deleting stale external router device: %s', stale_dev)
-            self.agent.pd.remove_gw_interface(self.router['id'])
-            self.driver.unplug(stale_dev,
-                               bridge=self.agent_conf.external_network_bridge,
-                               namespace=self.ns_name,
-                               prefix=EXTERNAL_DEV_PREFIX)
+        self._delete_stale_external_devices(interface_name)
 
         # Process SNAT rules for external gateway
         gw_port = self._router.get('gw_port')
diff --git a/neutron/tests/unit/agent/l3/test_agent.py b/neutron/tests/unit/agent/l3/test_agent.py
index 131b7d88d71..c7d17f8993a 100644
--- a/neutron/tests/unit/agent/l3/test_agent.py
+++ b/neutron/tests/unit/agent/l3/test_agent.py
@@ -1870,6 +1870,35 @@ class TestBasicRouterOperations(BasicRouterOperationsFramework):
             namespace=ri.ns_name,
             prefix=namespaces.EXTERNAL_DEV_PREFIX)
 
+    def test_process_dvr_router_delete_stale_external_devices(self):
+        agent = l3_agent.L3NATAgent(HOSTNAME, self.conf)
+        stale_devlist = [l3_test_common.FakeDev('qg-a1b2c3d4-e5')]
+        stale_devnames = [dev.name for dev in stale_devlist]
+
+        router = l3_test_common.prepare_router_data(enable_snat=True,
+                                                    num_internal_ports=1)
+        self._set_ri_kwargs(agent, router['id'], router)
+        ri = dvr_router.DvrEdgeRouter(HOSTNAME, **self.ri_kwargs)
+        self.mock_ip.get_devices.return_value = stale_devlist
+
+        ri.process()
+
+        self.mock_driver.unplug.assert_called_with(
+            stale_devnames[0],
+            bridge=agent.conf.external_network_bridge,
+            namespace=ri.snat_namespace.name,
+            prefix=namespaces.EXTERNAL_DEV_PREFIX)
+
+    def test_process_dvr_router_delete_stale_external_devices_no_snat_ns(self):
+        agent = l3_agent.L3NATAgent(HOSTNAME, self.conf)
+        router = l3_test_common.prepare_router_data(enable_gw=False,
+                                                    num_internal_ports=1)
+        self._set_ri_kwargs(agent, router['id'], router)
+        ri = dvr_router.DvrEdgeRouter(HOSTNAME, **self.ri_kwargs)
+        self.mock_ip.netns.exists.return_value = False
+        ri._delete_stale_external_devices('qg-a1b2c3d4-e5')
+        self.assertFalse(self.mock_ip.get_devices.called)
+
     def test_router_deleted(self):
         agent = l3_agent.L3NATAgent(HOSTNAME, self.conf)
         agent._queue = mock.Mock()