A confidence-boosting merger between Greece's second and third-largest lenders, Eurobank and Alpha Bank, is to be announced on Monday, a banking source said.
"The governing boards of the two banks will meet in the morning to approve the plan," the official told AFP on condition of anonymity.
"A press conference will later be held to announce the details surrounding the exchange of stocks, the governing framework and the capital increase provisions," he added.
Greek media reports have said that the new entity, Alpha Eurobank, would be the Balkans' largest lender with assets of 150 billion euros ($218 billion), 80 billion in deposits and 2,000 branches in southeastern Europe.
Qatar's state investment authority, which holds around five percent in Alpha Bank, will reportedly participate in the new venture with a stake of around 16 percent.
"Qatar will hold an important share," the banking source confirmed.
Announcements are expected around 1100 GMT.
Eurobank and Alpha are respectively the second and third Greek banks in terms of assets and capitalisation.
The move comes ahead of an audit of Greek bank holdings by BlackRock, the world's largest money manager, at the request of the Bank of Greece that is to begin next week.
Eurobank, which sold a Polish subsidiary and posted a net profit of 74 million euros in the first quarter of 2011 from 16 million euros a year earlier, pledged in July to boost its capital after failing EU-wide bank stress tests.
Alpha Bank, which saw its takings drop by 80 percent to 10.5 million euros in the first quarter, in February rejected a friendly merger offer from National Bank, the country's leading lender.
The deteriorating state of Greek public finances has cast a pall on the country's banking sector which has significant exposure to state debt, which has hit rock bottom after successive credit rating downgrades.
Greek banks have suffered as a result of debt-hit Greece's pariah status among creditors and have had to rely on the European Central Bank for fresh loans to keep them afloat.