diff --git a/neutron/agent/linux/ovs_lib.py b/neutron/agent/linux/ovs_lib.py
index 2072183992..5caa420451 100644
--- a/neutron/agent/linux/ovs_lib.py
+++ b/neutron/agent/linux/ovs_lib.py
@@ -208,7 +208,14 @@ class OVSBridge(BaseOVS):
 
     def defer_apply_off(self):
         LOG.debug(_('defer_apply_off'))
-        for action, flows in self.deferred_flows.items():
+        # Note(ethuleau): stash flows and disable deferred mode. Then apply
+        # flows from the stashed reference to be sure to not purge flows that
+        # were added between two ofctl commands.
+        stashed_deferred_flows, self.deferred_flows = (
+            self.deferred_flows, {'add': '', 'mod': '', 'del': ''}
+        )
+        self.defer_apply_flows = False
+        for action, flows in stashed_deferred_flows.items():
             if flows:
                 LOG.debug(_('Applying following deferred flows '
                             'to bridge %s'), self.br_name)
@@ -216,8 +223,6 @@ class OVSBridge(BaseOVS):
                     LOG.debug(_('%(action)s: %(flow)s'),
                               {'action': action, 'flow': line})
                 self.run_ofctl('%s-flows' % action, ['-'], flows)
-        self.defer_apply_flows = False
-        self.deferred_flows = {'add': '', 'mod': '', 'del': ''}
 
     def add_tunnel_port(self, port_name, remote_ip, local_ip,
                         tunnel_type=p_const.TYPE_GRE,
diff --git a/neutron/tests/unit/agent/linux/test_ovs_lib.py b/neutron/tests/unit/agent/linux/test_ovs_lib.py
index 96a7e8ee64..4b4231790d 100644
--- a/neutron/tests/unit/agent/linux/test_ovs_lib.py
+++ b/neutron/tests/unit/agent/linux/test_ovs_lib.py
@@ -407,6 +407,50 @@ class OVS_Lib_Test(base.BaseTestCase):
             mock.call('del-flows', ['-'], 'deleted_flow_1\n')
         ])
 
+    def test_defer_apply_flows_concurrently(self):
+        flow_expr = mock.patch.object(ovs_lib, '_build_flow_expr_str').start()
+        flow_expr.side_effect = ['added_flow_1', 'deleted_flow_1',
+                                 'modified_flow_1', 'added_flow_2',
+                                 'deleted_flow_2', 'modified_flow_2']
+
+        run_ofctl = mock.patch.object(self.br, 'run_ofctl').start()
+
+        def run_ofctl_fake(cmd, args, process_input=None):
+            self.br.defer_apply_on()
+            if cmd == 'add-flows':
+                self.br.add_flow(flow='added_flow_2')
+            elif cmd == 'del-flows':
+                self.br.delete_flows(flow='deleted_flow_2')
+            elif cmd == 'mod-flows':
+                self.br.mod_flow(flow='modified_flow_2')
+        run_ofctl.side_effect = run_ofctl_fake
+
+        self.br.defer_apply_on()
+        self.br.add_flow(flow='added_flow_1')
+        self.br.delete_flows(flow='deleted_flow_1')
+        self.br.mod_flow(flow='modified_flow_1')
+        self.br.defer_apply_off()
+
+        run_ofctl.side_effect = None
+        self.br.defer_apply_off()
+
+        flow_expr.assert_has_calls([
+            mock.call({'flow': 'added_flow_1'}, 'add'),
+            mock.call({'flow': 'deleted_flow_1'}, 'del'),
+            mock.call({'flow': 'modified_flow_1'}, 'mod'),
+            mock.call({'flow': 'added_flow_2'}, 'add'),
+            mock.call({'flow': 'deleted_flow_2'}, 'del'),
+            mock.call({'flow': 'modified_flow_2'}, 'mod')
+        ])
+        run_ofctl.assert_has_calls([
+            mock.call('add-flows', ['-'], 'added_flow_1\n'),
+            mock.call('del-flows', ['-'], 'deleted_flow_1\n'),
+            mock.call('mod-flows', ['-'], 'modified_flow_1\n'),
+            mock.call('add-flows', ['-'], 'added_flow_2\n'),
+            mock.call('del-flows', ['-'], 'deleted_flow_2\n'),
+            mock.call('mod-flows', ['-'], 'modified_flow_2\n')
+        ])
+
     def test_add_tunnel_port(self):
         pname = "tap99"
         local_ip = "1.1.1.1"