Parliament expected to be dissolved on Wednesday - President Giorgio Napolitano on Tuesday began procedures to dissolve parliament and set the nation on the path to elections.
In line with constitutional rules on the closure of a legislature, the head of state summoned the speakers of the House and Senate to see him in the Quirinal Palace in the early evening.
Napolitano's official announcement dissolving parliament - and closing the second shortest legislature in the history of the Republic (648 days) - was expected on Wednesday.
At that point it will be up to the centre-left government of Romano Prodi, in its caretaker capacity, to decide on the date of elections.
Most analysts expect the date will be April 13-14, a choice which would allow national elections to coincide with administrative ones in many parts of the country.
The moves to prepare for elections became inevitable after an attempt by Senate Speaker Franco Marini to drum up support for an interim government was steadfastly rejected by centre-right parties.
Napolitano had wanted parties to support a short-term government which would reform the electoral law and possibly make other institutional reforms.
But the centre right, led by former premier Silvio Berlusconi, said there was no need for a new electoral system to replace the one it pushed through parliament seven months before the 2006 elections.
According to most polls, a centre-right alliance led by Berlusconi, who is aiming to become premier for the third time, is likely to win spring elections handsomely.
The system under which Italians now look set to vote uses proportional representation and blocked lists of candidates who are allocated their seats in parliament by the parties.
Several analysts and centre-left politicians say the system has worsened the fragmentation of Italian politics and was a factor in the chronic instability of the collapsed government of Romano Prodi.
Napolitano had wanted rules changed so as to ensure that similar instability would not hobble the next government.
Berlusconi has said he is willing to engage in dialogue on electoral reform after the elections, which he is expected to win.
If politicians fail to agree on a new voting system, the law could be changed by referendum. The Constitutional Court has already approved a proposed referendum on the law and on Tuesday the cabinet set May 18 as the date to hold it.
The vote is expected to be postponed until 2009 because under the Italian Constitution a referendum must be postponed for a year if parliament is dissolved and the nation goes to the polls.
Referendum supporters want Italians to approve three changes to the current system. The first two would award an extra packet of parliamentary seats to whichever party won the most votes. At present this packet goes to the winning coalition.
Campaigners believe that this change will encourage small parties to merge into bigger ones, alleviating the perennial fragmentation of the Italian political scene.
The third question aims to stop the current practice of high-profile candidates standing in more than one constituency, using their visibility to attract more votes.
