diff --git a/deployment_scripts/remove_default_networks.sh b/deployment_scripts/remove_default_networks.sh
new file mode 100755
index 0000000..15c633e
--- /dev/null
+++ b/deployment_scripts/remove_default_networks.sh
@@ -0,0 +1,45 @@
+#!/bin/bash
+# This script removes default network config created in OpenStack as part of a
+# Fuel deployment. These networks do not work for instance creation with
+# Calico, so need to be removed.
+
+# OpenStack authentication and authorization requires environment variables
+# contained in the openrc file, this will allow us to issue commands via the 
+# neutron API.
+source /root/openrc
+
+# Details of the default networks/routers created on Fuel deployment of a
+# Mirantis OpenStack environment.
+DEFAULT_NET=net04
+DEFAULT_NET_EXT=net04_ext
+DEFAULT_ROUTER=router04
+
+# DEFAULT_NET_EXT is set as the gateway for DEFAULT_ROUTER, we must clear that
+# before we can delete the network.
+neutron router-gateway-clear $DEFAULT_ROUTER
+neutron net-delete $DEFAULT_NET_EXT
+
+# DEFAULT_NET cannot be deleted until all ports configured on the network have 
+# been removed. We get details of the configured ports from the "neutron port-list"
+# command, whose output is of the form:
+# +-----+------+-------------------+-----------------------------------------------+
+# | id  | name | mac_address       | fixed_ips                                     |
+# +-----+------+-------------------+-----------------------------------------------+
+# | foo |      | fa:16:3e:ae:70:4e | {"subnet_id": "bar", "ip_address": "a.b.c.d"} |
+# +-----+------+-------------------+-----------------------------------------------+
+port_ids=$(neutron port-list | grep "|" | grep -v "fixed_ips" | cut -d " " -f 2)
+for port_id in "${port_ids[@]}"
+do
+  neutron port-delete $port_id
+  if [[ $? != 0 ]]; then
+    # One of the ports is associated with the interface for the default router.
+    # This causes port deletion to fail. So we delete the interface on the
+    # router (this also removes the port).
+    neutron router-interface-delete $DEFAULT_ROUTER port=$port_id
+  fi
+done
+
+# We can now delete the default router and the default network.
+neutron router-delete $DEFAULT_ROUTER
+neutron net-delete $DEFAULT_NET
+
diff --git a/tasks.yaml b/tasks.yaml
index fe62e41..8fc69d0 100644
--- a/tasks.yaml
+++ b/tasks.yaml
@@ -16,6 +16,14 @@
     cmd: ./calico_route_reflector.sh
     timeout: 60
 
+# Remove default OpenStack network configuration which doesn't work with Calico.
+- role: ['primary-controller']
+  stage: post_deployment/150
+  type: shell
+  parameters:
+    cmd: ./remove_default_networks.sh
+    timeout: 60
+
 # Install/configure calico on the compute nodes after cluster deployment.
 - role: ['compute']
   stage: post_deployment