diff --git a/quantum/db/l3_db.py b/quantum/db/l3_db.py
index 506060fcbc..514d7a691d 100644
--- a/quantum/db/l3_db.py
+++ b/quantum/db/l3_db.py
@@ -740,8 +740,17 @@ class L3_NAT_db_mixin(l3.RouterPluginBase):
         if port_db['device_owner'] in [DEVICE_OWNER_ROUTER_INTF,
                                        DEVICE_OWNER_ROUTER_GW,
                                        DEVICE_OWNER_FLOATINGIP]:
-            raise l3.L3PortInUse(port_id=port_id,
-                                 device_owner=port_db['device_owner'])
+            # Raise port in use only if the port has IP addresses
+            # Otherwise it's a stale port that can be removed
+            fixed_ips = port_db['fixed_ips'].all()
+            if fixed_ips:
+                raise l3.L3PortInUse(port_id=port_id,
+                                     device_owner=port_db['device_owner'])
+            else:
+                LOG.debug(_("Port %(port_id)s has owner %(port_owner)s, but "
+                            "no IP address, so it can be deleted"),
+                          {'port_id': port_db['id'],
+                           'port_owner': port_db['device_owner']})
 
     def disassociate_floatingips(self, context, port_id):
         with context.session.begin(subtransactions=True):
diff --git a/quantum/tests/unit/test_l3_plugin.py b/quantum/tests/unit/test_l3_plugin.py
index 8d7414d672..509ba8fc58 100644
--- a/quantum/tests/unit/test_l3_plugin.py
+++ b/quantum/tests/unit/test_l3_plugin.py
@@ -968,6 +968,23 @@ class L3NatDBTestCase(L3NatTestCaseBase):
                     r['router']['id'],
                     n['network']['id'], expected_code=exc.HTTPBadRequest.code)
 
+    def test_delete_unused_router_interface(self):
+        with self.network() as n:
+            with self.router() as r:
+                with self.subnet(network=n) as s:
+                    res = self._create_port(self.fmt,
+                                            s['subnet']['network_id'])
+                    p = self.deserialize(self.fmt, res)
+                    self._router_interface_action('add',
+                                                  r['router']['id'],
+                                                  None,
+                                                  p['port']['id'])
+                # The subnet here is deleted, and the port should have no IP
+                self._delete('ports', p['port']['id'])
+                # Verify the port has been deleted
+                self._show('ports', p['port']['id'],
+                           expected_code=exc.HTTPNotFound.code)
+
     def test_router_remove_interface_inuse_returns_409(self):
         with self.router() as r:
             with self.subnet() as s: