Although speculation as to how long Greece can remain afloat has been rife for months, no one seems sure exactly how much money the country has left.
The dire situation was thrown into sharp relief in April when the government controversially ordered all local municipalities in the country to transfer their idle cash reserves to the Greek central bank.
Greece hopes to get 2.5 billion euros from state entities' cash reserves to cover its payment needs until the end of May, Reuters reported at the weekend. It has so far scraped together just over 600 million euros, a Greek government official, who declined to be named, confirmed to CNBC Wednesday.
As well as mounting payments to the IMF (Greece has to pay 1.5 billion euros in June) and interest payments on bonds held by the European Central Bank (ECB), Greece also has to pay its own public sector wages and pensions bill each month, which reportedly totaled 2 billion euros in April.
On Thursday, Greece's Finance Minister Yanis Varoufakis was reported by Reuters as saying Greece's payment of debt to the ECB over July and August should be pushed back.
According to the news wire service, Varoufakis suggested a debt swap to push back payments to the ECB would help Greece, but said that this would not occur because the idea filled ECB President Mario Draghi's "soul with fear."
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The pressures of such payments mean that a last tranche of a final tranche of bailout aid, worth 7.2 billion euros, is even more crucial for Greece to avoid default, although whether it can do so in the long term remains of concern to economists.