German Chancellor Angela Merkel is prepared to let Greece leave the eurozone if Greeks elect a government that jettisons the country's current austerity course, according to German media reports.

 The report in the Der Spiegel daily, which cited sources close to the German government, comes as polls show a radical leftist party leading the field three weeks ahead of a snap election in Greece.

The Syriza party of Alexis Tsipras has pledged to reverse reforms imposed by Greece's international creditors and renegotiate its bailout deal.

"The German government considers a eurozone exit (by Greece) to be almost inevitable if opposition leader Alexis Tsipras leads the government after the election and abandons budgetary discipline and does not repay the country's debts," Der Spiegel reported on its website.

Both Merkel and Finance Minister Wolfgang Schäuble had come to view a potential Greek exit from the 19-currency eurozone in a less dramatic light, the report explained.

They both now felt such an outcome would be "bearable", Der Spiegel quoted unnamed sources as saying.