diff --git a/src/history/base.js b/src/history/base.js
index 5f2bad870..f96e4d9ce 100644
--- a/src/history/base.js
+++ b/src/history/base.js
@@ -146,7 +146,9 @@ export class History {
             cb(err)
           })
         } else {
-          warn(false, 'uncaught error during route navigation:')
+          if (process.env.NODE_ENV !== 'production') {
+            warn(false, 'uncaught error during route navigation:')
+          }
           console.error(err)
         }
       }
diff --git a/src/index.js b/src/index.js
index 3cf38a496..4ffe2db57 100644
--- a/src/index.js
+++ b/src/index.js
@@ -39,6 +39,9 @@ export default class VueRouter {
   afterHooks: Array<?AfterNavigationHook>
 
   constructor (options: RouterOptions = {}) {
+    if (process.env.NODE_ENV !== 'production') {
+      warn(this instanceof VueRouter, `Router must be called with the new operator.`)
+    }
     this.app = null
     this.apps = []
     this.options = options
diff --git a/src/util/warn.js b/src/util/warn.js
index 025d3b20f..95564c1a9 100644
--- a/src/util/warn.js
+++ b/src/util/warn.js
@@ -7,7 +7,7 @@ export function assert (condition: any, message: string) {
 }
 
 export function warn (condition: any, message: string) {
-  if (process.env.NODE_ENV !== 'production' && !condition) {
+  if (!condition) {
     typeof console !== 'undefined' && console.warn(`[vue-router] ${message}`)
   }
 }