diff --git a/beetsplug/duplicates.py b/beetsplug/duplicates.py
index 632b7d772..5ca314d3f 100644
--- a/beetsplug/duplicates.py
+++ b/beetsplug/duplicates.py
@@ -20,7 +20,7 @@ from __future__ import division, absolute_import, print_function
 import shlex
 
 from beets.plugins import BeetsPlugin
-from beets.ui import decargs, print_, vararg_callback, Subcommand, UserError
+from beets.ui import decargs, print_, Subcommand, UserError
 from beets.util import command_output, displayable_path, subprocess
 from beets.library import Item, Album
 import six
@@ -80,10 +80,9 @@ class DuplicatesPlugin(BeetsPlugin):
             help=u'report duplicates only if all attributes are set',
         )
         self._command.parser.add_option(
-            u'-k', u'--keys', dest='keys',
-            action='callback', metavar='KEY1 KEY2',
-            callback=vararg_callback,
-            help=u'report duplicates based on keys',
+            u'-k', u'--key',
+            action='append', metavar='KEY',
+            help=u'report duplicates based on keys (use multiple times)',
         )
         self._command.parser.add_option(
             u'-M', u'--merge', dest='merge',