diff --git a/packages/google-api-servicecontrol/src/v1/quota_controller_client.ts b/packages/google-api-servicecontrol/src/v1/quota_controller_client.ts
index 679c2cb978f..7a26c4d3ba3 100644
--- a/packages/google-api-servicecontrol/src/v1/quota_controller_client.ts
+++ b/packages/google-api-servicecontrol/src/v1/quota_controller_client.ts
@@ -17,8 +17,13 @@
 // ** All changes to this file may be overwritten. **
 
 /* global window */
-import * as gax from 'google-gax';
-import {Callback, CallOptions, Descriptors, ClientOptions} from 'google-gax';
+import type * as gax from 'google-gax';
+import type {
+  Callback,
+  CallOptions,
+  Descriptors,
+  ClientOptions,
+} from 'google-gax';
 
 import * as protos from '../../protos/protos';
 import jsonProtos = require('../../protos/protos.json');
@@ -28,7 +33,6 @@ import jsonProtos = require('../../protos/protos.json');
  * This file defines retry strategy and timeouts for all API methods in this library.
  */
 import * as gapicConfig from './quota_controller_client_config.json';
-
 const version = require('../../../package.json').version;
 
 /**
@@ -90,8 +94,18 @@ export class QuotaControllerClient {
    *     Pass "rest" to use HTTP/1.1 REST API instead of gRPC.
    *     For more information, please check the
    *     {@link https://github.com/googleapis/gax-nodejs/blob/main/client-libraries.md#http11-rest-api-mode documentation}.
+   * @param {gax} [gaxInstance]: loaded instance of `google-gax`. Useful if you
+   *     need to avoid loading the default gRPC version and want to use the fallback
+   *     HTTP implementation. Load only fallback version and pass it to the constructor:
+   *     ```
+   *     const gax = require('google-gax/build/src/fallback'); // avoids loading google-gax with gRPC
+   *     const client = new QuotaControllerClient({fallback: 'rest'}, gax);
+   *     ```
    */
-  constructor(opts?: ClientOptions) {
+  constructor(
+    opts?: ClientOptions,
+    gaxInstance?: typeof gax | typeof gax.fallback
+  ) {
     // Ensure that options include all the required fields.
     const staticMembers = this.constructor as typeof QuotaControllerClient;
     const servicePath =
@@ -111,8 +125,13 @@ export class QuotaControllerClient {
       opts['scopes'] = staticMembers.scopes;
     }
 
+    // Load google-gax module synchronously if needed
+    if (!gaxInstance) {
+      gaxInstance = require('google-gax') as typeof gax;
+    }
+
     // Choose either gRPC or proto-over-HTTP implementation of google-gax.
-    this._gaxModule = opts.fallback ? gax.fallback : gax;
+    this._gaxModule = opts.fallback ? gaxInstance.fallback : gaxInstance;
 
     // Create a `gaxGrpc` object, with any grpc-specific options sent to the client.
     this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
@@ -166,7 +185,7 @@ export class QuotaControllerClient {
     this.innerApiCalls = {};
 
     // Add a warn function to the client constructor so it can be easily tested.
-    this.warn = gax.warn;
+    this.warn = this._gaxModule.warn;
   }
 
   /**
@@ -391,7 +410,7 @@ export class QuotaControllerClient {
     options.otherArgs = options.otherArgs || {};
     options.otherArgs.headers = options.otherArgs.headers || {};
     options.otherArgs.headers['x-goog-request-params'] =
-      gax.routingHeader.fromParams({
+      this._gaxModule.routingHeader.fromParams({
         service_name: request.serviceName || '',
       });
     this.initialize();
diff --git a/packages/google-api-servicecontrol/src/v1/service_controller_client.ts b/packages/google-api-servicecontrol/src/v1/service_controller_client.ts
index d7df5207b72..2f786e7d590 100644
--- a/packages/google-api-servicecontrol/src/v1/service_controller_client.ts
+++ b/packages/google-api-servicecontrol/src/v1/service_controller_client.ts
@@ -17,8 +17,13 @@
 // ** All changes to this file may be overwritten. **
 
 /* global window */
-import * as gax from 'google-gax';
-import {Callback, CallOptions, Descriptors, ClientOptions} from 'google-gax';
+import type * as gax from 'google-gax';
+import type {
+  Callback,
+  CallOptions,
+  Descriptors,
+  ClientOptions,
+} from 'google-gax';
 
 import * as protos from '../../protos/protos';
 import jsonProtos = require('../../protos/protos.json');
@@ -28,7 +33,6 @@ import jsonProtos = require('../../protos/protos.json');
  * This file defines retry strategy and timeouts for all API methods in this library.
  */
 import * as gapicConfig from './service_controller_client_config.json';
-
 const version = require('../../../package.json').version;
 
 /**
@@ -90,8 +94,18 @@ export class ServiceControllerClient {
    *     Pass "rest" to use HTTP/1.1 REST API instead of gRPC.
    *     For more information, please check the
    *     {@link https://github.com/googleapis/gax-nodejs/blob/main/client-libraries.md#http11-rest-api-mode documentation}.
+   * @param {gax} [gaxInstance]: loaded instance of `google-gax`. Useful if you
+   *     need to avoid loading the default gRPC version and want to use the fallback
+   *     HTTP implementation. Load only fallback version and pass it to the constructor:
+   *     ```
+   *     const gax = require('google-gax/build/src/fallback'); // avoids loading google-gax with gRPC
+   *     const client = new ServiceControllerClient({fallback: 'rest'}, gax);
+   *     ```
    */
-  constructor(opts?: ClientOptions) {
+  constructor(
+    opts?: ClientOptions,
+    gaxInstance?: typeof gax | typeof gax.fallback
+  ) {
     // Ensure that options include all the required fields.
     const staticMembers = this.constructor as typeof ServiceControllerClient;
     const servicePath =
@@ -111,8 +125,13 @@ export class ServiceControllerClient {
       opts['scopes'] = staticMembers.scopes;
     }
 
+    // Load google-gax module synchronously if needed
+    if (!gaxInstance) {
+      gaxInstance = require('google-gax') as typeof gax;
+    }
+
     // Choose either gRPC or proto-over-HTTP implementation of google-gax.
-    this._gaxModule = opts.fallback ? gax.fallback : gax;
+    this._gaxModule = opts.fallback ? gaxInstance.fallback : gaxInstance;
 
     // Create a `gaxGrpc` object, with any grpc-specific options sent to the client.
     this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
@@ -166,7 +185,7 @@ export class ServiceControllerClient {
     this.innerApiCalls = {};
 
     // Add a warn function to the client constructor so it can be easily tested.
-    this.warn = gax.warn;
+    this.warn = this._gaxModule.warn;
   }
 
   /**
@@ -393,7 +412,7 @@ export class ServiceControllerClient {
     options.otherArgs = options.otherArgs || {};
     options.otherArgs.headers = options.otherArgs.headers || {};
     options.otherArgs.headers['x-goog-request-params'] =
-      gax.routingHeader.fromParams({
+      this._gaxModule.routingHeader.fromParams({
         service_name: request.serviceName || '',
       });
     this.initialize();
@@ -513,7 +532,7 @@ export class ServiceControllerClient {
     options.otherArgs = options.otherArgs || {};
     options.otherArgs.headers = options.otherArgs.headers || {};
     options.otherArgs.headers['x-goog-request-params'] =
-      gax.routingHeader.fromParams({
+      this._gaxModule.routingHeader.fromParams({
         service_name: request.serviceName || '',
       });
     this.initialize();
diff --git a/packages/google-api-servicecontrol/src/v2/service_controller_client.ts b/packages/google-api-servicecontrol/src/v2/service_controller_client.ts
index 863f5900b32..f556caaaf6a 100644
--- a/packages/google-api-servicecontrol/src/v2/service_controller_client.ts
+++ b/packages/google-api-servicecontrol/src/v2/service_controller_client.ts
@@ -17,8 +17,13 @@
 // ** All changes to this file may be overwritten. **
 
 /* global window */
-import * as gax from 'google-gax';
-import {Callback, CallOptions, Descriptors, ClientOptions} from 'google-gax';
+import type * as gax from 'google-gax';
+import type {
+  Callback,
+  CallOptions,
+  Descriptors,
+  ClientOptions,
+} from 'google-gax';
 
 import * as protos from '../../protos/protos';
 import jsonProtos = require('../../protos/protos.json');
@@ -28,7 +33,6 @@ import jsonProtos = require('../../protos/protos.json');
  * This file defines retry strategy and timeouts for all API methods in this library.
  */
 import * as gapicConfig from './service_controller_client_config.json';
-
 const version = require('../../../package.json').version;
 
 /**
@@ -94,8 +98,18 @@ export class ServiceControllerClient {
    *     Pass "rest" to use HTTP/1.1 REST API instead of gRPC.
    *     For more information, please check the
    *     {@link https://github.com/googleapis/gax-nodejs/blob/main/client-libraries.md#http11-rest-api-mode documentation}.
+   * @param {gax} [gaxInstance]: loaded instance of `google-gax`. Useful if you
+   *     need to avoid loading the default gRPC version and want to use the fallback
+   *     HTTP implementation. Load only fallback version and pass it to the constructor:
+   *     ```
+   *     const gax = require('google-gax/build/src/fallback'); // avoids loading google-gax with gRPC
+   *     const client = new ServiceControllerClient({fallback: 'rest'}, gax);
+   *     ```
    */
-  constructor(opts?: ClientOptions) {
+  constructor(
+    opts?: ClientOptions,
+    gaxInstance?: typeof gax | typeof gax.fallback
+  ) {
     // Ensure that options include all the required fields.
     const staticMembers = this.constructor as typeof ServiceControllerClient;
     const servicePath =
@@ -115,8 +129,13 @@ export class ServiceControllerClient {
       opts['scopes'] = staticMembers.scopes;
     }
 
+    // Load google-gax module synchronously if needed
+    if (!gaxInstance) {
+      gaxInstance = require('google-gax') as typeof gax;
+    }
+
     // Choose either gRPC or proto-over-HTTP implementation of google-gax.
-    this._gaxModule = opts.fallback ? gax.fallback : gax;
+    this._gaxModule = opts.fallback ? gaxInstance.fallback : gaxInstance;
 
     // Create a `gaxGrpc` object, with any grpc-specific options sent to the client.
     this._gaxGrpc = new this._gaxModule.GrpcClient(opts);
@@ -170,7 +189,7 @@ export class ServiceControllerClient {
     this.innerApiCalls = {};
 
     // Add a warn function to the client constructor so it can be easily tested.
-    this.warn = gax.warn;
+    this.warn = this._gaxModule.warn;
   }
 
   /**
@@ -404,7 +423,7 @@ export class ServiceControllerClient {
     options.otherArgs = options.otherArgs || {};
     options.otherArgs.headers = options.otherArgs.headers || {};
     options.otherArgs.headers['x-goog-request-params'] =
-      gax.routingHeader.fromParams({
+      this._gaxModule.routingHeader.fromParams({
         service_name: request.serviceName || '',
       });
     this.initialize();
@@ -517,7 +536,7 @@ export class ServiceControllerClient {
     options.otherArgs = options.otherArgs || {};
     options.otherArgs.headers = options.otherArgs.headers || {};
     options.otherArgs.headers['x-goog-request-params'] =
-      gax.routingHeader.fromParams({
+      this._gaxModule.routingHeader.fromParams({
         service_name: request.serviceName || '',
       });
     this.initialize();