Opposition leader Silvio Berlusconi said on Monday he would not support an interim government to guide Italy out of a political crisis, making a snap election appear inevitable.

Italy's 61st government since World War Two collapsed last month after Prime Minister Romano Prodi lost a confidence vote in parliament following defections in his coalition.

Loath to send Italians back to the polls less than two years after the last vote, President Giorgio Napolitano asked the speaker of the Senate to try to form a temporary government and reform voting rules blamed for the instability of Prodi's government.

But former prime minister Berlusconi, sensing a quick return to power, has dug in his heels and demanded elections now. "We hope -- and we think that's what will happen -- that after these consultations the head of state will call elections immediately, because the country quickly needs an efficient government to solve its grave problems," the 71-year old said.

Berlusconi, the only prime minister to have served a full five-year term in post-war Italy, and his main conservative ally Gianfranco Fini met Senate speaker Franco Marini on Monday for the final stage of talks on a way out of the political vacuum.

Both told Marini, a Catholic centre-leftist with broad appeal, that elections were the only option and electoral reform could wait. A vote could be held as early as April.

Walter Veltroni, Prodi's heir as centre-left leader who would face Berlusconi in an election, also met Marini on Monday.

"I think this risks being a missed opportunity for Italian politics, rushing towards elections with a flawed law," he said. Marini is expected to report back to Napolitano later on Monday.

Business leaders pleaded for stability following Prodi's resignation after just 20 months in office.

Employers' group head Luca Cordero di Montezemolo, who favours electoral reform, urged an end to "years of rivalry and ungovernability so that we can guarantee growth, because we grow less than any other European country".

Many economists also say another government elected under current rules will prove just as unstable as Prodi's.

POISON PILL

Prodi quit after constant arguing in his nine-party alliance coalition came to a head with the defection of a small Catholic party, which erased his tiny majority in the Senate.

His government's inherent fragility resulted largely from voting rules introduced by Berlusconi in 2005 and regarded by critics as a "poison pill" for Prodi, who won the 2006 election by the slimmest margin in Italy's modern history.

Even the right-wing senator who drew up that reform called it "rubbish" and Berlusconi recently held talks with Veltroni, head of the main centre-left Democratic Party (PD), about possible changes.

But when Prodi's government collapsed, Berlusconi changed his tune.

The media tycoon, in mourning for the death of his 97-year-old mother on Sunday, said there was no need to change the rules now. He said opinion polls estimated he had a lead over the centre left of between 10 and 16 points.

Veltroni, Rome's popular mayor who at 52 is one of the younger faces in Italian politics, believes the PD can put up a fight only by running alone, without its bickering Catholic and communist allies. That depends on first changing voting rules which favour coalitions and give great power to small parties.

Il Giornale newspaper -- owned by Berlusconi's brother Paolo -- even speculated about an electoral pact between the man known as "Il Cavaliere" (the Knight) and Veltroni. Berlusconi said this was a "utopian" fantasy.