diff --git a/packages/webpack-cli/lib/utils/cli-flags.js b/packages/webpack-cli/lib/utils/cli-flags.js
index 5264a2146e5..ce949b3078c 100644
--- a/packages/webpack-cli/lib/utils/cli-flags.js
+++ b/packages/webpack-cli/lib/utils/cli-flags.js
@@ -1,3 +1,4 @@
+const { logger } = require('@webpack-cli/logger');
 const HELP_GROUP = 'help';
 const CONFIG_GROUP = 'config';
 const BASIC_GROUP = 'basic';
@@ -286,11 +287,16 @@ module.exports = {
         {
             name: 'mode',
             usage: '--mode <development | production>',
-            type: String,
+            type: (value) => {
+                if (value === 'development' || value === 'production' || value === 'none') {
+                    return value
+                } else {
+                    logger.warn('You provided an invalid value for "mode" option.')
+                }
+            },
             group: ZERO_CONFIG_GROUP,
             description: 'Defines the mode to pass to webpack',
-            link: 'https://webpack.js.org/concepts/#mode',
-            acceptedValues: ["development", "production"]
+            link: 'https://webpack.js.org/concepts/#mode'
         },
         {
             name: 'no-mode',
diff --git a/test/help/__snapshots__/help-single-arg.test.js.snap b/test/help/__snapshots__/help-single-arg.test.js.snap
index 3ef3bcec597..079bf435b25 100644
--- a/test/help/__snapshots__/help-single-arg.test.js.snap
+++ b/test/help/__snapshots__/help-single-arg.test.js.snap
@@ -44,7 +44,7 @@ Options
   --standard               Prints standard output                               
   -d, --dev                Run development build                                
   -p, --prod               Run production build                                 
-  --mode string            Defines the mode to pass to webpack                  
+  --mode type              Defines the mode to pass to webpack                  
   --no-mode                Sets mode="none" which disables any default behavior 
   --version                Get current version                                  
   --node-args string[]     NodeJS flags