Lazy loading modules with angular-router-loader errors with cannot find module "."

Webpack has trouble finding a module that I am trying to lazy load with angular-router-loader.

I am using the following:
Webpack 2.2.1
Angular 5.2
angular-router-loader 0.8.2

Installed the angular-router-loader via npm, and added the loader to my webpack config::

       {
            test: /\.ts$/,
            use: ['awesome-typescript-loader', 'angular2-template-loader'],
            exclude: [/\.(spec|e2e)\.ts$/]
        },
        {
            test: /\.(ts|js)$/,
            loaders: [
              'angular-router-loader'
            ]
        },

The project layout looks like this:

app/
  - app.routing.ts
  authenticated/
    property/
      - property.module.ts
      setup/
         - propertysetup.component.ts

In app.routing.ts:

const appRoutes: Routes = [
  {path: 'property', canActivate: [AuthGuard],
    loadChildren: './authenticated/property/property.module#PropertyModule'
  }
];

property.module.ts:

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { Routes, RouterModule } from '@angular/router';
import { PropertySetupComponent } from './setup/propertysetup.component';

const routes: Routes = [
  {
    path: 'setup',
    component: PropertySetupComponent
  }
];

@NgModule({
  imports: [
    RouterModule.forChild(routes),
    CommonModule
  ],
  exports: [
    RouterModule
  ],
  declarations: [
    PropertySetupComponent
  ]
})
export class PropertyModule { }

When I start webpack dev server, I can see in the console that angular-router-loader is replacing the string defined in loadChildren section of app.routing.ts:

[angular-router-loader]: --DEBUG--
[angular-router-loader]: File: e:\eclipse_workspace\projectNG\projectFrontend\src\app\app.routing.ts
[angular-router-loader]: Original: loadChildren: './authenticated/property/property.module#PropertyModule'
[angular-router-loader]: Replacement: loadChildren: function() { return new Promise(function (resolve, reject) {  (require as any).ensure([], function (require:
any) {    resolve(require('.\\authenticated\\property\\property.module')

But I get the following warning from webpack:

WARNING in ./src/app/app.routing.ts
44:84-91 Critical dependency: require function is used in a way in which dependencies cannot be statically extracted

Then when I try to go to the path (http://localhost:3000/#/property/setup) in a browser, I get the following stack trace error from the browser console:

 ERROR Error: Uncaught (in promise): Error: Cannot find module "."
    Error: Cannot find module "."
        at webpackMissingModule (eval at 903 (app.js:1618), <anonymous>:44:129)
        at eval (eval at 903 (app.js:1618), <anonymous>:44:208)
        at new ZoneAwarePromise (eval at <anonymous> (polyfills.js:4031), <anonymous>:875:29)
        at loadChildren (eval at 903 (app.js:1618), <anonymous>:44:44)
        at RouterConfigLoader.loadModuleFactory (eval at <anonymous> (vendor.js:156), <anonymous>:4647:109)

I have tried replacing the module path in loadChildren with an absolute path as well. E.g.

loadChildren: 'app/authenticated/property/property.module#PropertyModule'

But I get exactly the same warning from webpack, and error in the browser console as above.
I think I have followed the installation / usage instructions correctly from here: https://github.com/brandonroberts/angular-router-loader

Any suggestions / help much appreciated.