Former Premier Silvio Berlusconi's tax fraud conviction and four-year prison sentence were upheld on the first appeal Wednesday in a case that could see him barred from public office for five years.

In Italy, defendants are legally considered innocent until all appeals are exhausted, and Berlusconi's lawyers are expected to appeal the case to the nation's highest Court of Cassation once the reasoning for the decision is published.

Still, the ruling, which comes just days before prosecutors wrap up closing arguments in his sensational sex-for-hire trial, raises the question of whether Berlusconi's days as a political force are numbered.

His center-right forces are allied with the Democratic Party in a grand coalition, and although Berlusconi holds no governmental posts he remains influential. It was his decision to head the center-right coalition, after initially saying he would move aside for younger leaders, that gave a boost to his forces in February's election campaign, finishing a close second to the center-left.