Christian Lindner, chairman of the liberal Free Democratic Party FDP addresses the media in Berlin, Germany, March 14, 2016. REUTERS/Wolfgang Rattay

BERLIN (Reuters) - Greece should leave the euro zone and then be given debt relief, the head of Germany’s pro-business Free Democrats (FDP) told a German radio station on Thursday.

Greece should, however, remain in the European Union, FDP leader Christian Lindner told Deutschlandfunk, so it can get subsidies to put into infrastructure or help small- and medium-sized businesses.

“It’s clear that Greece needs to have its debts written off,” Lindner said. “Greece’s debts can only be written off outside of the euro zone, so we’re talking about Grexit.”

Recent polls put support for the FDP, which was the junior coalition partner to Chancellor Angela Merkel’s conservatives from 2009 to 2013, at 5 to 7 percent. That suggests it will get enough support to cross the 5 percent threshold to enter the Bundestag lower house of parliament in elections on Sept. 24.

Lindner said Greek Prime Minister Alexis Tsipras did not intend to implement agreed reforms, so the strategy needed to be changed.

The German government wants the International Monetary Fund to have a stake in Greece’s bailout to give the rescue plan greater credibility. But it opposes granting Athens the significant debt relief that the IMF is demanding.

On Friday, Finance Minister Wolfgang Schaeuble said Greece must meet commitments it has made under its international bailout plans or else it will end up in an impossible position .