diff --git a/src/mixin.js b/src/mixin.js
index ea6b2ac98..7272e8833 100644
--- a/src/mixin.js
+++ b/src/mixin.js
@@ -10,6 +10,19 @@ export default {
 
     if (options.i18n) {
       if (options.i18n instanceof VueI18n) {
+        // init locale messages via custom blocks
+        if (options.__i18n) {
+          try {
+            const localeMessages = JSON.parse(options.__i18n)
+            Object.keys(localeMessages).forEach((locale: Locale) => {
+              options.i18n.mergeLocaleMessage(locale, localeMessages[locale])
+            })
+          } catch (e) {
+            if (process.env.NODE_ENV !== 'production') {
+              warn(`Cannot parse locale messages via custom blocks.`)
+            }
+          }
+        }
         this._i18n = options.i18n
         this._i18nWatcher = this._i18n.watchI18nData(() => this.$forceUpdate())
       } else if (isPlainObject(options.i18n)) {
diff --git a/test/unit/issues.test.js b/test/unit/issues.test.js
index bd639fc5e..1b3d8f0cd 100644
--- a/test/unit/issues.test.js
+++ b/test/unit/issues.test.js
@@ -70,4 +70,26 @@ describe('issues', () => {
       )
     })
   })
+
+  describe('#169', () => {
+    it('should be translated', done => {
+      const Component = Vue.extend({
+        __i18n: JSON.stringify({
+          en: { custom: 'custom block!' }
+        }),
+        render (h) {
+          return h('p', { ref: 'custom' }, [this.$t('custom')])
+        }
+      })
+      const vm = new Component({
+        i18n: new VueI18n({
+          locale: 'en',
+          messages
+        })
+      }).$mount()
+      nextTick(() => {
+        assert.equal(vm.$refs.custom.textContent, 'custom block!')
+      }).then(done)
+    })
+  })
 })