ROME (Reuters) - Former Italian prime minister Silvio Berlusconi's final appeal against a prison term for tax fraud is expected to be heard in court on July 30, much earlier than expected, his lawyers said on Tuesday. The surprise timetabling heightened the pressures on Prime Minister Enrico Letta's fragile coalition government, which depends on the 76-year-old Berlusconi's center-right People of Freedom party (PDL). Although he may avoid jail due to his age, a ban on public office, depriving him of his seat in parliament, could deepen the problems bedeviling a government already divided over key elements of tax and economic policy. Berlusconi, who often says leftist magistrates want to destroy him politically, is not a minister but plays a big behind-the-scenes role ensuring the stability of the coalition with his traditional rivals in the center-left Democratic Party (PD). Berlusconi was sentenced last year to four years' jail with a five-year ban on holding public office, for complicity in tax fraud at his Mediaset television empire, a decision that was upheld on appeal in May. A final appeal had been expected at the end of the year with reports in Italian newspapers speculating that the court could run into the statute of limitations at least on some of the charges, potentially curbing any sentence against Berlusconi. However the decision to schedule the final appeal hearing before the normal summer break caught his legal team offguard and drew a furious reaction. I am astonished," one of Berlusconi's lawyers, Franco Coppi, told Reuters. If the verdict against the billionaire media tycoon is upheld, he will have no more right of appeal. In a caustic comment on the timing of the hearing, Gaetano Quagliariello, minister for constitutional reform and a member of the PDL, said it contrasted sharply with the normal snail's pace of the Italian justice system. "One can only hope that people will realize that the question of justice is not only a problem for Silvio Berlusconi or the center-right but is affecting our whole state," he said in a statement. Berlusconi has pledged to continue supporting Letta's coalition but some hardline allies in his party have threatened protests if the verdict goes against him. The tax fraud trial is only one of a series of legal battles against Berlusconi, who was sentenced last month to seven years' jail for paying for sex with a minor in the "bunga bunga" case involving former teenaged nightclub dancer Karima El Mahroug, alias "Ruby the Heartstealer." Writing by James Mackenzie; Editing by Mark Heinrich