Chancellor Angela Merkel admitted Monday that Germany benefited from a decision by Balkan nations to close their borders to migrants seeking to head north, even as she insisted that it was not a long-term solution.

"It is unquestionable that Germany benefits from (the route closure, but) we can see from pictures out of Greece that that is not a sustainable solution," she told journalists a day after her party suffered a drubbing in state polls over her liberal refugee policy.

Germany, which last year recorded thousands of asylum seekers arriving daily, has seen numbers drop significantly since western Balkan states shut down the route used by migrants.