The Institute of International Finance said that a Greek random default could trigger more than one trillion euros of losses and also could leave Italy and Spain vulnerable, which in result could force both nations to seek an outside financial support to prevent the contagion from spreading within the economies.

The Institute of International Finance mentioned in a document obtained by Reuters that there are some very important and damaging ramifications that would result from a disorderly default on Greek government debt.

It is difficult to add all these contingent liabilities up with any degree of precision, although it is hard to see how they would not exceed 1 trillion euros.

The IIF attempts to convince bondholders to accept the debt-swap deal by Thursday, as this deal is expected to relieve Greece from 100 billion euros of the existing debt.

The European Central Bank's exposure to Greece is estimated around 177 billion euros. Ireland and Portugal could need around 380 billion euros over the coming 5 years, according to the IIF.

Moreover, Spain and Italy may need around 350 billion euros to prevent the contagion from spreading further in case Greece went through default, while Banks need around 160 billion euros for recapitalization, the IIF said.