One of Premier Romano Prodi's centrist allies warned on Tuesday that it will provoke a government crisis if a referendum on the country's electoral law goes ahead.
"I'm saying this clearly. If there is a referendum, before it takes place there will be a government crisis," said Justice Minister Clemente Mastella, leader of the small Udeur party.
Prodi has recently held talks with both centre-left and centre-right parties on changing Italy's electoral system, a reform seen as essential for improving political stability.
Small parties in both coalitions are keen to agree on a reform before a referendum campaign gets under way and takes the issue out of their hands.
The referendum is being promoted by a 158-strong committee which includes civil rights activists and politicians from both sides and its main aim is to force parties to run by themselves rather than in coalitions.
With the application of cut-off thresholds, this would slash the number of parties in parliament, eliminating the smaller ones, and encourage parties to merge.
Prodi's talks with the various parties have so far produced no clear bipartisan consensus.
An electoral reform pushed through parliament by his predecessor Silvio Berlusconi just four months before the April 2006 election controversially returned Italy to full proportional representation (PR) after a break of 13 years.
The new voting system assured Prodi a workable majority in the House but not the Senate, where the premier holds two more seats than the Berlusconi-led opposition.
This precarious situation has left Prodi weak and at the mercy of the numerous small parties in his fractious alliance and their conflicting demands.
Prodi briefly resigned in February after the government lost a Senate foreign policy vote.
The premier survived the ensuing crisis but President Giorgio Napolitano subsequently called on parliament to swiftly approve electoral reforms to boost political stability and governability.
Prodi said recently that he would like to replace PR with a system based on first-past-the-post contests in individual constituencies.
However, such a system is unlikely to win the support of the small parties in his coalition, six of whom gained less than 2.6% of the vote in the last general election.
