diff --git a/packages/compiler-cli/src/ngcc/src/analysis/private_declarations_analyzer.ts b/packages/compiler-cli/src/ngcc/src/analysis/private_declarations_analyzer.ts
new file mode 100644
index 0000000000..26d3f839a0
--- /dev/null
+++ b/packages/compiler-cli/src/ngcc/src/analysis/private_declarations_analyzer.ts
@@ -0,0 +1,60 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import * as ts from 'typescript';
+
+import {ReferencesRegistry} from '../../../ngtsc/annotations';
+import {Declaration} from '../../../ngtsc/host';
+import {NgccReflectionHost} from '../host/ngcc_host';
+import {hasNameIdentifier, isDefined} from '../utils';
+
+export interface ExportInfo {
+  identifier: string;
+  from: string;
+  dtsFrom: string|null;
+}
+export type PrivateDeclarationsAnalyses = ExportInfo[];
+
+/**
+ * This class will analyze a program to find all the declared classes
+ * (i.e. on an NgModule) that are not publicly exported via an entry-point.
+ */
+export class PrivateDeclarationsAnalyzer {
+  constructor(private host: NgccReflectionHost, private referencesRegistry: ReferencesRegistry) {}
+
+  analyzeProgram(program: ts.Program): PrivateDeclarationsAnalyses {
+    const rootFiles = this.getRootFiles(program);
+    return this.getPrivateDeclarations(rootFiles, this.referencesRegistry.getDeclarationMap());
+  }
+
+  private getRootFiles(program: ts.Program): ts.SourceFile[] {
+    return program.getRootFileNames().map(f => program.getSourceFile(f)).filter(isDefined);
+  }
+
+  private getPrivateDeclarations(
+      rootFiles: ts.SourceFile[],
+      declarations: Map<ts.Identifier, Declaration>): PrivateDeclarationsAnalyses {
+    const privateDeclarations: Map<ts.Identifier, Declaration> = new Map(declarations);
+    rootFiles.forEach(f => {
+      const exports = this.host.getExportsOfModule(f);
+      if (exports) {
+        exports.forEach((declaration, exportedName) => {
+          if (hasNameIdentifier(declaration.node) && declaration.node.name.text === exportedName) {
+            privateDeclarations.delete(declaration.node.name);
+          }
+        });
+      }
+    });
+    return Array.from(privateDeclarations.keys()).map(id => {
+      const from = id.getSourceFile().fileName;
+      const declaration = privateDeclarations.get(id) !;
+      const dtsDeclaration = this.host.getDtsDeclarationOfClass(declaration.node);
+      const dtsFrom = dtsDeclaration && dtsDeclaration.getSourceFile().fileName;
+      return {identifier: id.text, from, dtsFrom};
+    });
+  }
+}
diff --git a/packages/compiler-cli/src/ngcc/test/analysis/private_declarations_analyzer_spec.ts b/packages/compiler-cli/src/ngcc/test/analysis/private_declarations_analyzer_spec.ts
new file mode 100644
index 0000000000..9188a5344b
--- /dev/null
+++ b/packages/compiler-cli/src/ngcc/test/analysis/private_declarations_analyzer_spec.ts
@@ -0,0 +1,158 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {ResolvedReference} from '@angular/compiler-cli/src/ngtsc/metadata';
+import * as ts from 'typescript';
+
+import {NgccReferencesRegistry} from '../../src/analysis/ngcc_references_registry';
+import {PrivateDeclarationsAnalyzer} from '../../src/analysis/private_declarations_analyzer';
+import {Esm2015ReflectionHost} from '../../src/host/esm2015_host';
+import {getDeclaration, makeTestBundleProgram, makeTestProgram} from '../helpers/utils';
+
+const TEST_PROGRAM = [
+  {
+    name: '/src/entry_point.js',
+    isRoot: true,
+    contents: `
+    export {PublicComponent} from './a';
+    export {ModuleA} from './mod';
+    export {ModuleB} from './b';
+  `
+  },
+  {
+    name: '/src/a.js',
+    isRoot: false,
+    contents: `
+    import {Component} from '@angular/core';
+    export class PublicComponent {}
+    PublicComponent.decorators = [
+      {type: Component, args: [{selectors: 'a', template: ''}]}
+    ];
+  `
+  },
+  {
+    name: '/src/b.js',
+    isRoot: false,
+    contents: `
+    import {Component, NgModule} from '@angular/core';
+    class PrivateComponent {}
+    PrivateComponent.decorators = [
+      {type: Component, args: [{selectors: 'b', template: ''}]}
+    ];
+    export class ModuleB {}
+    ModuleB.decorators = [
+      {type: NgModule, args: [{declarations: [PrivateComponent]}]}
+    ];
+  `
+  },
+  {
+    name: '/src/c.js',
+    isRoot: false,
+    contents: `
+    import {Component} from '@angular/core';
+    export class InternalComponent {}
+    InternalComponent.decorators = [
+      {type: Component, args: [{selectors: 'c', template: ''}]}
+    ];
+  `
+  },
+  {
+    name: '/src/mod.js',
+    isRoot: false,
+    contents: `
+    import {Component, NgModule} from '@angular/core';
+    import {PublicComponent} from './a';
+    import {ModuleB} from './b';
+    import {InternalComponent} from './c';
+    export class ModuleA {}
+    ModuleA.decorators = [
+      {type: NgModule, args: [{
+        declarations: [PublicComponent, InternalComponent],
+        imports: [ModuleB]
+      }]}
+    ];
+  `
+  }
+];
+const TEST_DTS_PROGRAM = [
+  {
+    name: '/typings/entry_point.d.ts',
+    isRoot: true,
+    contents: `
+    export {PublicComponent} from './a';
+    export {ModuleA} from './mod';
+    export {ModuleB} from './b';
+  `
+  },
+  {
+    name: '/typings/a.d.ts',
+    isRoot: false,
+    contents: `
+    export declare class PublicComponent {}
+  `
+  },
+  {
+    name: '/typings/b.d.ts',
+    isRoot: false,
+    contents: `
+    export declare class ModuleB {}
+  `
+  },
+  {
+    name: '/typings/c.d.ts',
+    isRoot: false,
+    contents: `
+    export declare class InternalComponent {}
+  `
+  },
+  {
+    name: '/typings/mod.d.ts',
+    isRoot: false,
+    contents: `
+    import {PublicComponent} from './a';
+    import {ModuleB} from './b';
+    import {InternalComponent} from './c';
+    export declare class ModuleA {}
+  `
+  },
+];
+
+describe('PrivateDeclarationsAnalyzer', () => {
+  describe('analyzeProgram()', () => {
+    it('should find all NgModule declarations that were not publicly exported from the entry-point',
+       () => {
+         const program = makeTestProgram(...TEST_PROGRAM);
+         const dts = makeTestBundleProgram(TEST_DTS_PROGRAM);
+         const host = new Esm2015ReflectionHost(false, program.getTypeChecker(), dts);
+         const referencesRegistry = new NgccReferencesRegistry(host);
+         const analyzer = new PrivateDeclarationsAnalyzer(host, referencesRegistry);
+
+         // Set up the registry with references - this would normally be done by the
+         // decoration handlers in the `DecorationAnalyzer`.
+         const publicComponentDeclaration =
+             getDeclaration(program, '/src/a.js', 'PublicComponent', ts.isClassDeclaration);
+         referencesRegistry.add(
+             new ResolvedReference(publicComponentDeclaration, publicComponentDeclaration.name !));
+         const privateComponentDeclaration =
+             getDeclaration(program, '/src/b.js', 'PrivateComponent', ts.isClassDeclaration);
+         referencesRegistry.add(new ResolvedReference(
+             privateComponentDeclaration, privateComponentDeclaration.name !));
+         const internalComponentDeclaration =
+             getDeclaration(program, '/src/c.js', 'InternalComponent', ts.isClassDeclaration);
+         referencesRegistry.add(new ResolvedReference(
+             internalComponentDeclaration, internalComponentDeclaration.name !));
+
+         const analyses = analyzer.analyzeProgram(program);
+         expect(analyses.length).toEqual(2);
+         expect(analyses).toEqual([
+           {identifier: 'PrivateComponent', from: '/src/b.js', dtsFrom: null},
+           {identifier: 'InternalComponent', from: '/src/c.js', dtsFrom: '/typings/c.d.ts'},
+         ]);
+       });
+  });
+});