Greece's exit from the euro will be «unavoidable» if anti-austerity radicals win a June 17 election and halt painful economic reforms, a leading German conservative was quoted on Wednesday as saying.

Alexander Dobrindt, deputy leader of the Christian Social Union (CSU), one of three parties in Chancellor Angela Merkel's centre-right coalition, has said in the past Greece may be better off outside the euro, but his latest comments underscore Berlin's growing exasperation with Greek politicians.

"On election day the hour strikes for the Greek euro. If the communists or other radicals win the election, Greece's exit from the euro zone will be unavoidable,» Dobrindt told the top-selling Bild daily.

"Europe cannot and should not acquiesce if the Greek radical leftists make good on their declaration that they will unilaterally halt the repayment of aid loans and break off reforms,» he said.

The tough spending cuts, tax hikes and other reforms agreed with international lenders in return for 130 billion euros worth of loans are not negotiable, said Dobrindt.

Other German politicians, including Merkel and Finance Minister Wolfgang Schaeuble, have also urged Greece to stick to its austerity programme following big gains by anti-bailout parties in a previous inconclusive election on May 6.

But they have stopped short of publicly warning of a Greek exit from the single currency in the event of a victory by anti-bailout parties.

Alexis Tsipras, the charismatic young leader of Greece's biggest anti-bailout party, pressed his case during a visit to Berlin on Tuesday for an end to austerity in his country but he did not meet with members of Merkel's coalition.

Merkel and other EU leaders were due to meet in Brussels on Wednesday evening to discuss new ways to revive flagging economic growth in the euro zone.

[Reuters]