Italy's President Giorgio Napolitano is holding a series of meetings with senior politicians to try to agree on a new caretaker government after PM Silvio Berlusconi resigned on Saturday.
It is hoped the new government will be named before the world's financial markets re-open on Monday.
Ex-EU commissioner Mario Monti remains favourite to take the top job.
But he may face stiff opposition as he tries to implement stringent austerity measures, correspondents say.
Mr Napolitano is holding 17 meetings throughout Sunday with the last set for 17:15 (16:15 GMT).
The new prime minister will be responsible for implementing austerity measures aimed at tackling Italy's debt crisis, which last week saw its cost of borrowing rise to record levels and prompted alarm across the eurozone.
Amid the crisis, Mr Berlusconi lost his parliamentary majority and promised to resign once measures demanded by the EU and designed to restore markets' confidence in the country's economy had been passed by both houses of parliament.