ROME (Reuters) -- Italy's Senate speaker gave up trying to form a temporary government on Monday, making a snap election the only likely way out of a political vacuum left when Romano Prodi resigned as prime minister last month.

Senate speaker Franco Marini, who had been asked by the president to seek cross-party backing for an interim administration to reform the electoral system ahead of a vote, said there was no such support.
""I could not find a significant majority on a precise electoral reform,"" Marini told reporters as he left President Giorgio Napolitano's office after handing back his mandate to try to form a new government.
Napolitano has little choice now but to dissolve parliament and call an election that is likely to take place by mid-April.
That is the outcome favored by opposition leader Silvio Berlusconi, who is riding high in opinion polls and hopes to return to the office of prime minister he has held twice before.
""We hope -- and we think that's what will happen -- that ... 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 after meeting Marini on Monday.
Napolitano could theoretically ask Marini or someone else to try again, but that is considered very unlikely as Berlusconi's center-right bloc is sure to reject any further advances.
Italy's 61st post-war government collapsed last month after Prime Minister Prodi lost a confidence vote in parliament following defections from his center-left coalition.
Walter Veltroni, Prodi's heir as center-left leader who would face Berlusconi in an election, had hoped for a delay.
""I think this risks being a missed opportunity for Italian politics, rushing towards elections with a flawed law,"" he said.
Business leaders have pleaded for stability following Prodi's resignation after just 20 months in office.
Employers' group head Luca Cordero di Montezemolo, who favors 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.
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 center left of between 10 and 16 points.
Veltroni, Rome's popular mayor who at 52 is one of the younger faces in Italian politics, has said he wants the PD to run alone, without its bickering Catholic and communist allies -- something which might be tricky without the electoral reform.