diff --git a/remotefilelog/__init__.py b/remotefilelog/__init__.py
--- a/remotefilelog/__init__.py
+++ b/remotefilelog/__init__.py
@@ -1008,7 +1008,8 @@
     ], _('hg repack [OPTIONS]'))
 def repack(ui, repo, *pats, **opts):
     if opts.get('background'):
-        repackmod.backgroundrepack(repo, incremental=opts.get('incremental'))
+        repackmod.backgroundrepack(repo, incremental=opts.get('incremental'),
+                                   packsonly=opts.get('packsonly', False))
         return
 
     options = {'packsonly': opts.get('packsonly')}
diff --git a/remotefilelog/repack.py b/remotefilelog/repack.py
--- a/remotefilelog/repack.py
+++ b/remotefilelog/repack.py
@@ -28,12 +28,14 @@
 
 osutil = policy.importmod(r'osutil')
 
-def backgroundrepack(repo, incremental=True):
+def backgroundrepack(repo, incremental=True, packsonly=False):
     cmd = [util.hgexecutable(), '-R', repo.origroot, 'repack']
     msg = _("(running background repack)\n")
     if incremental:
         cmd.append('--incremental')
         msg = _("(running background incremental repack)\n")
+    if packsonly:
+        cmd.append('--packsonly')
     cmd = ' '.join(map(util.shellquote, cmd))
 
     repo.ui.warn(msg)