diff --git a/modules/net-cloudnat/README.md b/modules/net-cloudnat/README.md
index 64342ad33c..9e18ff644d 100644
--- a/modules/net-cloudnat/README.md
+++ b/modules/net-cloudnat/README.md
@@ -63,7 +63,6 @@ module "nat" {
 # tftest modules=2 resources=5 inventory=rules.yaml
 ```
 <!-- BEGIN TFDOC -->
-
 ## Variables
 
 | name | description | type | required | default |
@@ -76,7 +75,7 @@ module "nat" {
 | [config_source_subnets](variables.tf#L39) | Subnetwork configuration (ALL_SUBNETWORKS_ALL_IP_RANGES, ALL_SUBNETWORKS_ALL_PRIMARY_IP_RANGES, LIST_OF_SUBNETWORKS). | <code>string</code> |  | <code>&#34;ALL_SUBNETWORKS_ALL_IP_RANGES&#34;</code> |
 | [config_timeouts](variables.tf#L45) | Timeout configurations. | <code title="object&#40;&#123;&#10;  icmp            &#61; optional&#40;number, 30&#41;&#10;  tcp_established &#61; optional&#40;number, 1200&#41;&#10;  tcp_transitory  &#61; optional&#40;number, 30&#41;&#10;  udp             &#61; optional&#40;number, 30&#41;&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> |  | <code>&#123;&#125;</code> |
 | [logging_filter](variables.tf#L57) | Enables logging if not null, value is one of 'ERRORS_ONLY', 'TRANSLATIONS_ONLY', 'ALL'. | <code>string</code> |  | <code>null</code> |
-| [router_asn](variables.tf#L78) | Router ASN used for auto-created router. | <code>number</code> |  | <code>64514</code> |
+| [router_asn](variables.tf#L78) | Router ASN used for auto-created router. | <code>number</code> |  | <code>null</code> |
 | [router_create](variables.tf#L84) | Create router. | <code>bool</code> |  | <code>true</code> |
 | [router_name](variables.tf#L90) | Router name, leave blank if router will be created to use auto generated name. | <code>string</code> |  | <code>null</code> |
 | [router_network](variables.tf#L96) | Name of the VPC used for auto-created router. | <code>string</code> |  | <code>null</code> |
@@ -93,5 +92,4 @@ module "nat" {
 | [region](outputs.tf#L32) | Cloud NAT region. |  |
 | [router](outputs.tf#L37) | Cloud NAT router resources (if auto created). |  |
 | [router_name](outputs.tf#L46) | Cloud NAT router name. |  |
-
 <!-- END TFDOC -->
diff --git a/modules/net-cloudnat/main.tf b/modules/net-cloudnat/main.tf
index 68613c4d47..6d1da01d8d 100644
--- a/modules/net-cloudnat/main.tf
+++ b/modules/net-cloudnat/main.tf
@@ -28,8 +28,12 @@ resource "google_compute_router" "router" {
   project = var.project_id
   region  = var.region
   network = var.router_network
-  bgp {
-    asn = var.router_asn
+
+  dynamic "bgp" {
+    for_each = var.router_asn == null ? [] : [1]
+    content {
+      asn = var.router_asn
+    }
   }
 }
 
diff --git a/modules/net-cloudnat/variables.tf b/modules/net-cloudnat/variables.tf
index abf0641506..ed2649aacc 100644
--- a/modules/net-cloudnat/variables.tf
+++ b/modules/net-cloudnat/variables.tf
@@ -78,7 +78,7 @@ variable "region" {
 variable "router_asn" {
   description = "Router ASN used for auto-created router."
   type        = number
-  default     = 64514
+  default     = null
 }
 
 variable "router_create" {