ROME - A trial of Prime Minister Silvio Berlusconi on tax fraud charges resumes on Monday, the first of a series of showdowns between the scandal-hit leader and Italy's judiciary that will take centre stage over coming months.

The case involves the acquisition of television rights by Italy's biggest private broadcaster Mediaset , the crown jewel in Berlusconi's vast business empire.

The premier and other Mediaset executives are accused of inflating the price paid for purchasing TV rights via offshore companies controlled by Berlusconi and skimming off part of the sums declared to create illegal slush funds.

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The Milan trial was effectively put on hold for a year but is now resuming after the constitutional court stripped Berlusconi of automatic immunity from prosecution.

Two related trials will recommence in early March while a separate case, in which Berlusconi is accused of paying for sex with an under-aged nightclub dancer and abusing the powers of his office to try to cover up the affair, begins on April 6.

Berlusconi, who is unlikely to appear in court on Monday, denies the charges in all of the cases and says politically motivated leftist magistrates are out to destroy him.

The trials come at a delicate juncture for the 74 year-old conservative premier. His mounting judicial woes and Italy's sluggish economy are weighing on his popularity.

On February 13 an estimated one million protesters - mostly women - took to the streets demanding his resignation and, for the first time since he triumphantly returned to power in 2008, some opinion polls show the chronically divided centre-left opposition edging ahead if early elections were held.

Italian Prime Minister Silvio Berlusconi touches his eye as he delivers his speech during a meeting in Rome Feb 26, 2011. Berlusconi, mired in a prostitution scandal, faces a tax fraud trial on Monday, the first of four court cases that will bring his legal woes back into the spotlight over coming months. [Photo/Agencies]

But at the same time he has managed to push back the prospect of snap polls by beefing up his parliamentary majority, which had been cut to a handful of votes after last year's split with longtime ally Gianfranco Fini and his supporters.

Having lured back several lawmakers from Fini's breakaway movement, Berlusconi appears to have regained the upper hand - even if by a narrow margin.

On Sunday, he vowed to see out his term until it ends in 2013, saying early elections would hurt heavily-indebted Italy's government bonds, and pledged a sweeping reform of the judiciary which he accuses of trying to oust him from power.

He also said he opposed gay marriage and legal rights for unwed couples, in what commentators said was an attempt to reach out to the Vatican and Catholic voters critical of his lifestyle.

Still, Berlusconi can hardly rejoice at the prospect of a protracted legal battle that will revive juvenile prostitution allegations which have made headlines around the world and prompted growing calls for him to step down.

"This puts him in an uncomfortable position, and the pressure will build once the most embarrassing case starts - the trial over his relations with young women," said Franco Pavoncello, political science professor at John Cabot university.

Dozens of showgirls and aspiring starlets who prosecutors say received cash and gifts after attending Berlusconi's parties and allegedly taking part in sex games could be called to take the stand in that trial.