Gianni Alemanno, a close ally of Prime Minister-elect Silvio Berlusconi, won a run-off election for mayor of Rome, becoming the first right-winger to run Italy's capital since the fascists in 1943.

Mr Alemanno, 50, a member of the right-wing National Alliance party who ran on a law-and-order campaign, won with 53.7 per cent, according to preliminary results.

Francesco Rutelli, a former Rome mayor from the centre-left Democratic Party, took 46.3.

The win was an unexpected bonus for Mr Berlusconi, whose centre-right overwhelmingly won an April 13-14 national election and already holds power in the financial capital, Milan.

Mr Berlusconi hailed it as a "historic victory" that "cemented our success" at the national election.

The National Alliance, one of Mr Berlusconi's two main allies, has tried to ditch its fascist roots over the past decade and turn into a mainstream conservative force.

But Mr Alemanno has come under attack for wearing a Celtic cross around his neck - a symbol of the far right in Italy, where a 1993 law compared it to the Nazi swastika.

"I'll be the mayor of all Romans," Mr Alemanno said after his victory over the centre left, which has run Rome for most of the past 30 years and continuously since 1993.

"A system of power that seemed perfect has collapsed and disappeared," said Mr Alemanno, who served as Agriculture Minister in Berlusconi's last governments.

Commentators say losing the city of 2.5 million after 15 years leaves the centre left in disarray, compounding its defeat in the national election.

With its wealth of archaeological treasures, Renaissance art and churches, Rome is a tourists' paradise that attracts millions of visitors every year.