Greece hurtled Saturday towards a crunch bailout referendum which could determine its financial future and even its place in the eurozone, as polls showed the 'Yes' and 'No' camps neck and neck.

On the eve of the vote that could also make or break the radical-left government, Greeks were increasing spooked by rumours that capital controls were leading to food and medicine shortages, as was growing uncertainty over when the country's banks would re-open.

"I've heard shops are running out of flour, sugar and salt. I'm really worried, how will we manage if we can't get to our money and there's no food to buy?" Lena Antoniou, a 35-year old mother of two, told AFP.

Nikos Archondis from the Panhellenic Exporters Association (PEA) told AFP "certain supermarkets are very concerned because they cannot forecast how the situation will evolve," adding that stocks of meat, cheeses, fruits and vegetables "risk running low in the following weeks".

Many businesses said they had been forced to ask workers to take unpaid leave, some shops were refusing card payments in an effort to hoard cash and there were reports of companies paying workers in IOUs valid in local supermarkets.

"No-one accepts your credit cards. Most people are buying food now because they fear the worst," said Andreas Koutras, a 51-year old who works in finance.

'Malicious rumour'

Prime Minister Alexis Tsipras got a rock-star welcome at an Athens rally late Friday as he sought to revive support for the 'No' vote in a referendum called to strengthen his hand in talks with international creditors.

EU leaders have warned that a 'No' victory could cause Greece to crash out of the eurozone. But Tsipras and his closest ally Finance Minister Yanis Varoufakis have accused them of fear-mongering.

In an interview published Saturday the outspoken Varoufakis accused Athens's creditors of "terrorism".

"What they're doing with Greece has a name -- terrorism," he told the Spanish El Mundo daily. "What Brussels and the troika want today is for the 'Yes' (vote) to win so they could humiliate the Greeks."

As tensions rose he was forced to deny a Financial Times report that suggested Greek savers could lose 30 percent of their bank deposits to shore up the banking system, slamming it a "malicious rumour".

The British business daily, quoting unidentified bankers and businessmen close to negotiations, reported that Greek depositors with over 8,000 euros ($8,900) in an account may be force to take a "haircut".

A defiant Tsipras told 25,000 cheering supporters at Friday's rally to "say 'No' to ultimatums and to turn your back on those who would terrorise you," adding: "No one can ignore this passion and optimism."

A rival rally of 22,000 "Yes" supporters shouted pro-European slogans and voiced fears of a so-called "Grexit" from the eurozone and a return to Greece's former currency, the drachma, if Tsipras got his way.

"They cannot pretend any longer that it's not about leaving the euro," said a 43-year-old doctor who gave his first name as Nikos. "Outside the euro lies only misery."

Many Greeks have crossed over to the "Yes" camp since capital controls were imposed this week limiting daily ATM withdrawals to just 60 euros ($67) in order to stem a cash haemorrhage after Greece's international aid package ran out on Tuesday.

Adding to the sense of crisis, a eurozone emergency fund officially declared Greece to be in default on Friday for not making a 1.5-billion-euro payment to the International Monetary Fund this week.

The latest voter intention polls, published late Friday, showed the nation of 11 million people was evenly divided.

A GPO poll put the 'Yes' voters at 44.1 percent and the 'Nos' at 43.7 percent, while an Alco survey found 44.5 percent would vote 'Yes' while 43.9 percent would vote 'No'.

'Wild revenge intentions'

Tsipras says the vote is needed to force creditors to finally accept his key demand of another round of debt relief to save Greece from financial meltdown and possibly crashing out of the euro.

But critics have complained the referendum's very technical bailout question is unintelligible, and that the bailout deal it asks voters to weigh expired on Tuesday.

European Commission chief Jean-Claude Juncker warned in Brussels that Greece's negotiating position would be "dramatically weakened" in the event of a "No" -- and still difficult even in the event of a "Yes" vote.

As the clock ticked down there was palpable exasperation among Greece's eurozone partners, at least one of whom branded the government as "amateurs" asking for a blank cheque.

The pitiful state of the country's banking sector was being blamed on Greeks who, gripped by panic, moved money to bank accounts in France and Germany or are stashing cash at home.

European leaders fear the referendum will not only seal Greece's fate; Eurosceptic parties at the extreme left and right of the political spectrum have been exploiting the Greek referendum to bash the euro currency.

Tsipras insists Greece needs to trim its suffocating 323-billion-euro debt burden by having creditors forgive 30 percent of what they are owed and allowing a 20-year grace period for repaying the rest.

Varoufakis has promised banks would reopen on Tuesday if a new deal is agreed quickly, and the Union of Greek Banks said Friday its members had enough liquidity until then.

In a op-ed in Greece's Kathimerini newspaper the minister warned a 'Yes' vote would transform the country into a "colony regime subject to debt", with creditors "returning to Athens with wild revenge intentions".