diff --git a/neutron/agent/linux/openvswitch_firewall/firewall.py b/neutron/agent/linux/openvswitch_firewall/firewall.py
index d11275e40a5..87e487dd68b 100644
--- a/neutron/agent/linux/openvswitch_firewall/firewall.py
+++ b/neutron/agent/linux/openvswitch_firewall/firewall.py
@@ -575,6 +575,13 @@ class OVSFirewallDriver(firewall.FirewallDriver):
     def _update_flows_for_port(self, of_port, old_of_port):
         with self.update_cookie_context():
             self._set_port_filters(of_port)
+        # Flush the flows caused by changes made to deferred bridge. The reason
+        # is that following delete_all_port_flows() call uses --strict
+        # parameter that cannot be combined with other non-strict rules, hence
+        # all parameters with --strict are applied right away. In order to
+        # avoid applying delete rules with --strict *before*
+        # _set_port_filters() we dump currently cached flows here.
+        self.int_br.apply_flows()
         self.delete_all_port_flows(old_of_port)
         # Rewrite update cookie with default cookie
         self._set_port_filters(of_port)
diff --git a/neutron/tests/common/conn_testers.py b/neutron/tests/common/conn_testers.py
index 1d8b7a4309f..fd6de6ec043 100644
--- a/neutron/tests/common/conn_testers.py
+++ b/neutron/tests/common/conn_testers.py
@@ -308,7 +308,8 @@ class ConnectionTester(fixtures.Fixture):
         except KeyError:
             src_namespace, dst_address = self._get_namespace_and_address(
                 direction)
-            pinger = net_helpers.Pinger(src_namespace, dst_address)
+            pinger = net_helpers.Pinger(
+                src_namespace, dst_address, interval=0.3)
             self._pingers[direction] = pinger
         return pinger
 
diff --git a/neutron/tests/common/net_helpers.py b/neutron/tests/common/net_helpers.py
index 6f8af60833d..303d1ca7a00 100644
--- a/neutron/tests/common/net_helpers.py
+++ b/neutron/tests/common/net_helpers.py
@@ -352,7 +352,8 @@ class Pinger(object):
         r'.* Destination .* Unreachable')
     TIMEOUT = 15
 
-    def __init__(self, namespace, address, count=None, timeout=1):
+    def __init__(self, namespace, address, count=None, timeout=1,
+                 interval=None):
         self.proc = None
         self.namespace = namespace
         self.address = address
@@ -361,6 +362,7 @@ class Pinger(object):
         self.destination_unreachable = False
         self.sent = 0
         self.received = 0
+        self.interval = interval
 
     def _wait_for_death(self):
         is_dead = lambda: self.proc.poll() is not None
@@ -390,6 +392,8 @@ class Pinger(object):
         cmd = [ping_exec, self.address, '-W', str(self.timeout)]
         if self.count:
             cmd.extend(['-c', str(self.count)])
+        if self.interval:
+            cmd.extend(['-i', str(self.interval)])
         self.proc = RootHelperProcess(cmd, namespace=self.namespace)
 
     def stop(self):
diff --git a/neutron/tests/unit/agent/linux/openvswitch_firewall/test_firewall.py b/neutron/tests/unit/agent/linux/openvswitch_firewall/test_firewall.py
index 67d46fb722c..0685ae82def 100644
--- a/neutron/tests/unit/agent/linux/openvswitch_firewall/test_firewall.py
+++ b/neutron/tests/unit/agent/linux/openvswitch_firewall/test_firewall.py
@@ -609,6 +609,16 @@ class TestOVSFirewallDriver(base.BaseTestCase):
         self.firewall.update_port_filter(port_dict)
         self.assertTrue(self.mock_bridge.br.delete_flows.called)
 
+    def test_update_port_filter_applies_added_flows(self):
+        """Check flows are applied right after _set_flows is called."""
+        port_dict = {'device': 'port-id',
+                     'security_groups': [1]}
+        self._prepare_security_group()
+        self.firewall.prepare_port_filter(port_dict)
+        with self.firewall.defer_apply():
+            self.firewall.update_port_filter(port_dict)
+        self.assertEqual(2, self.mock_bridge.apply_flows.call_count)
+
     def test_remove_port_filter(self):
         port_dict = {'device': 'port-id',
                      'security_groups': [1]}