Some of Greece's biggest banks may have to shut and merge with their rivals, it has been claimed.
A European official told the Reuters news agency that Greece's four big banks - National Bank of Greece, Eurobank, Piraeus and Alpha Bank - could be reduced to just two.
European leaders are meeting on Sunday in a bid to strike a financial aid deal with Greece.
Greek Prime Minister Alexis Tsipras has told the EU Parliament that very early retirement schemes should be ended.
Greece promised to put in place pension and tax reforms as early as next week as the first step to securing a three-year rescue loan to cover debt obligations.
According to a letter requesting the funding from European partners Greece also pledges to honour its financial obligations and detail by Thursday reforms proposals for evaluation by the creditors.
The letter welcomed an "opportunity to explore potential measures" to make its debt sustainable, as part of broader discussions to be held.
The Greeks have voted to reject the austerity terms demanded by eurozone creditors - so, what happens next?
Greeks have voted to reject the terms of an international bailout, putting it on the brink of a eurozone exit.
Greece's controversial Finance Minister Yanis Varoufakis has released a defiant statement of resignation entitled 'Minister no more!'