diff --git a/source/cli.js b/source/cli.js
index ca419747..01c33807 100755
--- a/source/cli.js
+++ b/source/cli.js
@@ -6,7 +6,7 @@ const logSymbols = require('log-symbols');
 const meow = require('meow');
 const updateNotifier = require('update-notifier');
 const hasYarn = require('has-yarn');
-const npmName = require('npm-name');
+const {isPackageNameAvailable} = require('./npm-util');
 const version = require('./version');
 const util = require('./util');
 const ui = require('./ui');
@@ -73,7 +73,7 @@ process.on('SIGINT', () => {
 (async () => {
 	const pkg = util.readPkg();
 
-	const isAvailable = cli.flags.publish ? await npmName(pkg.name) : false;
+	const isAvailable = cli.flags.publish ? await isPackageNameAvailable(pkg) : false;
 
 	const options = cli.input.length > 0 ?
 		{
diff --git a/source/npm-util.js b/source/npm-util.js
index 84d7d793..cc76fe8f 100644
--- a/source/npm-util.js
+++ b/source/npm-util.js
@@ -2,6 +2,7 @@
 const execa = require('execa');
 const pTimeout = require('p-timeout');
 const ow = require('ow');
+const npmName = require('npm-name');
 
 exports.checkConnection = () => pTimeout(
 	(async () => {
@@ -61,3 +62,14 @@ exports.prereleaseTags = async packageName => {
 
 	return tags;
 };
+
+exports.isPackageNameAvailable = async pkg => {
+	const isExternalRegistry = exports.isExternalRegistry(pkg);
+	if (isExternalRegistry) {
+		return true;
+	}
+
+	return npmName(pkg.name);
+};
+
+exports.isExternalRegistry = pkg => typeof pkg.publishConfig === 'object' && typeof pkg.publishConfig.registry === 'string';
diff --git a/source/prerequisite-tasks.js b/source/prerequisite-tasks.js
index 3309c763..a87a13a1 100644
--- a/source/prerequisite-tasks.js
+++ b/source/prerequisite-tasks.js
@@ -7,7 +7,7 @@ const npm = require('./npm-util');
 const {getTagVersionPrefix} = require('./util');
 
 module.exports = (input, pkg, options) => {
-	const isExternalRegistry = typeof pkg.publishConfig === 'object' && typeof pkg.publishConfig.registry === 'string';
+	const isExternalRegistry = npm.isExternalRegistry(pkg);
 	let newVersion = null;
 
 	const tasks = [