Greece must stick to the austerity commitments it has made if it wants to remain part of the eurozone after elections on June 17, German Chancellor Angela Merkel said on Friday.

Speaking after talks with New Zealand's prime minister John Key, Merkel said: "What we have always said is that we want Greece to remain a member of the eurozone."

"The precondition for that to succeed is that the future Greek government sticks to the memorandum that was agreed with the International Monetary Fund, European Central Bank and the European Commission."

Greece holds a fresh round of elections on June 17 after an indecisive vote on May 6 resulted in some 70 percent of voters supporting parties opposed to more austerity measures contained in the memorandum Merkel referred to.

Latest polls show the leftist Syriza party, which has vowed to tear up the memorandum with Greece's international partners, running neck-and-neck with the pro-austerity New Democracy.

"This memorandum is the foundation for a favourable development and we have to say that clearly to all those who are seeking election in Greece," Merkel stressed.

The memorandum is part of a deal struck with Greece's international creditors that demands billions of euros (dollars) in spending cuts in return for bailout cash and a debt writedown to keep the country afloat.

Critics argue it has made the situation worse by plunging the country into a deep recession.

EU leaders meeting in Brussels for an informal summit on May 23 declared they wanted Greece "to remain in the euro area while respecting its commitments".