"Now it's up to us to form a new government in the timescale that will be set out by the president," Prodi told reporters.

Ciampi, whose seven-year term ends on May 18, has yet to say whether he will start consultations this week on the formation of a government, or whether he will continue to favour waiting until after parliament elects a new head of state.

That would mean Italy would not have a new government until after parliament elects a new president -- an often arduous process that could be eased if the 85-year-old Ciampi bows to pressure to stand for a second term.

Both Berlusconi's centre-right House of Freedoms coalition and Prodi said on Tuesday they supported giving Ciampi a second term. Prodi expressed his hope that "the absence of a government does not go on for long".

In a move that could speed up the creation of a new government, the speaker of the lower house convened parliament and representatives of Italy's 20 regions on May 8 for the presidential election, earlier than the scheduled May 12-13.

Prodi, a former European Commission president, has said Italy could give the markets a sign of stability if his government gets down to work quickly. Credit ratings agencies are urging Italy to shore up its finances or risk a downgrade.

Berlusconi had denounced widespread irregularities in the vote, but Italy's Supreme Court sanctioned the count and said any further complaints should be reviewed by the new parliament.