Greece's economy faces "irreparable" damage from the ongoing political crisis, the boss of its central bank has warned.
"The crisis in recent days is now taking serious dimensions...and the risk of irreparable damage for the Greek economy is now great," said Yannis Stournaras.
Greek politicians will start voting on Wednesday for a new Greek president.
There will be a snap general election if the government nominee loses.
The political uncertainty has rattled Greek markets over the past week.
Greece's economy emerged from a six-year long recession in the first quarter of the year.
However, the size of Greece's economy is still about a quarter below the peak it reached before the severe recession and debt crisis triggered by the global financial crash.
And conservative Prime Minister Antonis Samaras's decision to call an early vote in parliament to elect a new president has caused fresh concerns.
His conservative-led coalition needs the support of other parties if its candidate is to obtain the backing of MPs.
On Thursday an official in the governing coalition said it was still short of the support needed to stop the government collapsing in the parliamentary vote.
Greece's government has warned of a catastrophe if snap elections are called and left-wing anti-bailout party Syriza wins, but Syriza has accused the government of fear mongering.