Prime Minister John Key says the Greek situation underlined his view that the biggest risk to New Zealand's economic growth came from overseas markets.

While Tsipras' decision to hold a ballot increased the risk of Greece exiting the euro, evidence of contagion elsewhere was limited.

It's a tricky enough situation already, buried under financial jargon with regular breaking developments. And now it's even more confusing.

Capital controls are on the way, with all the disruptions to everyday economic activity that they entail - and Greek banks will stay closed for a week.

With its banks closed, automated cash withdrawals restricted and a big debt payment due tonight, Greece surely cannot continue to defy its creditors.

Currency traders will be on tenterhooks this week as the Greek sovereign debt crisis goes from bad to worse, with more downward pressure likely to come on the Kiwi dollar.

The message for anyone trying the cashpoint at the National Bank of Greece in central Athens was curt and to the point.

It is crunch time for Greece. Again. Yes, you've heard that before, probably many times since the country's debt crisis first blew up around 2009.

Greek Prime Minister Alexis Tsipras says he will call a referendum on the outcome of the negotiations with international creditors.

Pacific Investment Management Co Chief Executive Officer Douglas Hodge says investors have had three years to prepare.

Greece lurched closer to an exit from the euro as a meeting of finance officials to reach a deal over aid dissolved in acrimony, forcing leaders to call for an emergency summit for Tuesday.

Greek Prime Minister Alexis Tsipras escalated his defiance towards the country's official creditors, with a pointed attack on the International Monetary Fund.

Greece was on the brink of economic meltdown as Germany looked poised to push the country out of the eurozone.

Greece faces a week of urgent diplomacy to free up bailout aid and avert a potential default as world leaders press for a final resolution to the standoff.

Of the many wonders to behold in Greece, Matt Derr has found a gem: local wine at $3 a glass.

Greece will be unable to find the 1.6 billion ($2.4 billion) sum it is due to hand the International Monetary Fund (IMF) next month, one of the country's ministers has admitted.

That Apple should buy Greece with all the useless cash it has on hand is just a joke that won't go away.

Like a spoilt child and an angry parent locked in an experiment of tough love, Greece and its creditors are embroiled once more in a tug-of-war.

Countries that default on their IMF obligations often experience widespread disruption to their cross-border financial relations.

Anti-austerity protesters seeking to spoil the inauguration of the ECB's new HQ in Frankfurt left a trail of destruction across the city.

Greek Prime Minister Alexis Tsipras won four more months to sell his policy program to creditors while keeping domestic voters on board.

Greek Prime Minister Alexis Tsipras began the task of selling domestically a provisional deal with eurozone partners to extend bailout funds after securing a reprieve.

It seems history is repeating itself as Greece again finds itself in the headlines, asking Germany to re-think the terms of the bailout package or risk Greece leaving the European union.

Kiwi broadcaster Dennis Katsanos rediscovers his Greek heritage - and adds 4kg in weight.

Greece has lost a critical funding artery as the European Central Bank restricts loans to its financial system.

Greek voters have sent Europe's leaders a message: the austerity policy you have been pursuing in recent years is economically perverse, socially cruel and ultimately subversive.

Alexis Tsipras was sworn in as the new Prime Minister of Greece, after his radical left-wing movement forged an unwieldy alliance with a far-right party.

Alexis Tsipras was sworn in as the new prime minister of Greece after his radical Left-wing movement forged an unwieldy alliance with a far-Right party.