diff --git a/.changelog/6550.txt b/.changelog/6550.txt
new file mode 100644
index 00000000000..0436bda4218
--- /dev/null
+++ b/.changelog/6550.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+compute: fixed unable to update `most_disruptive_allowed_action` for both `google_compute_per_instance_config` and `google_compute_region_per_instance_config`
+```
diff --git a/google/resource_compute_per_instance_config.go b/google/resource_compute_per_instance_config.go
index 07605bf0a8d..0483a84c683 100644
--- a/google/resource_compute_per_instance_config.go
+++ b/google/resource_compute_per_instance_config.go
@@ -381,8 +381,8 @@ func resourceComputePerInstanceConfigUpdate(d *schema.ResourceData, meta interfa
 	}
 	obj["minimalAction"] = minAction
 
-	mostDisruptiveAction := d.Get("most_disruptive_action_allowed")
-	if mostDisruptiveAction != "" {
+	mostDisruptiveAction := d.Get("most_disruptive_allowed_action")
+	if isEmptyValue(reflect.ValueOf(mostDisruptiveAction)) {
 		mostDisruptiveAction = "REPLACE"
 	}
 	obj["mostDisruptiveActionAllowed"] = mostDisruptiveAction
diff --git a/google/resource_compute_region_per_instance_config.go b/google/resource_compute_region_per_instance_config.go
index fa32ada3008..322ef02ed35 100644
--- a/google/resource_compute_region_per_instance_config.go
+++ b/google/resource_compute_region_per_instance_config.go
@@ -390,8 +390,8 @@ func resourceComputeRegionPerInstanceConfigUpdate(d *schema.ResourceData, meta i
 	}
 	obj["minimalAction"] = minAction
 
-	mostDisruptiveAction := d.Get("most_disruptive_action_allowed")
-	if mostDisruptiveAction != "" {
+	mostDisruptiveAction := d.Get("most_disruptive_allowed_action")
+	if isEmptyValue(reflect.ValueOf(mostDisruptiveAction)) {
 		mostDisruptiveAction = "REPLACE"
 	}
 	obj["mostDisruptiveActionAllowed"] = mostDisruptiveAction