The referendum Greek Prime Minister George Papandreou plans to hold on the new debt relief program proposed by the EU and International Monetary Fund threatens the financial stability of Greece and the eurozone, Fitch rating agency said in a statement on Tuesday.
"A rejection of the EU-IMF program recently negotiated by the Greek government would increase the risk of a forced and disorderly sovereign default and potentially a Greek exit from the euro. Both of which would have severe financial implications for the financial stability and viability of the eurozone," the statement said.
On October 26, EU states reached a deal to write off 50 percent of Greece's debt and provide the country with up to 100 billion euro ($140 billion) of financial support from the 'troika' of its lenders - the IMF, European Commission and European Central Bank.
But the deal stipulates tough austerity measures for Greece until 2020.
"The uncertainty over whether Greece will accept the EU-IMF program and private sector involvement also increases the uncertainty around the losses that creditors may incur and hence bank recapitalization," the statement said.
It is highly uncertain what would be the consequences of a 'no' vote. In the light of hard and prolonged negotiations between Greece and the troika, securing agreement on a new package could prove unobtainable, said Fitch.
Without continuing external financial support Greece may face a sovereign default given the heavy debt repayment schedule in the first quarter of 2012.
"Failure to provide a comprehensive and credible response to the Greek crisis has been a source of contagion and financial instability and has heightened a downward pressure on the ratings of other eurozone sovereigns," the statement also said.