Silvio Berlusconi on Sunday affirmed his centre-right movement's loyalty to the grand coalition government of Prime Minister Enrico Letta at a rally in a northern city which attracted noisy support and dissent.

"We believe in the government and we loyally support it because it is committed to achieving measures which we regard as vital for reviving the economy," former prime minister Berlusconi told the crowds in Brescia.

"Contracts between right-minded people are respected" and "I am a loyal person" he told them.

Berlusconi's People of Freedom party won nearly a third of the vote in February elections and is now a key partner in the grand coalition government, a move that surprised his party militants.

"It is only by being in the government that we can implement our remedies to overcome the current (economic) crisis," the 76-year-old billionaire argued.

His comments in a town square were accompanied by both applause and whistles of disapproval and shouts of "buffoon".

Berlusconi responded to the protestors by saying "his love is stronger than their envy and hatred".

Dissent within his own party is not the only problem facing the larger-than-life media tycoon.

Last week an Italian court upheld a tax fraud conviction against him, confirming his sentence of one year in prison and a five-year ban from public office.

Berlusconi is expected to appeal the ruling in Italy's highest court, which would suspend the punishment pending a final ruling in the case which revolves around his Mediaset business empire.

Berlusconi is also on trial for having sex with an underage 17-year-old prostitute while he was still prime minister, and then abusing the powers of his office by putting pressure on police to release her from custody.

In an interview with Canale 5 channel Sunday, Berlusconi insisted he had "absolutely never had intercourse with Ruby".

A verdict in that case is expected imminently.

Berlusconi was also convicted in March over the publication of police wiretap transcripts in a newspaper he owns, which were leaked in order to discredit a political rival.

He is appealing that conviction.

Prosecutors are also seeking a trial against Berlusconi for allegedly bribing a left-wing senator with 3.0 million euros ($4.0 million) to encourage him to join his party.

Berlusconi has been found guilty on various business-related charges in the past but all his convictions have either been overturned on appeal or have expired under the statute of limitations.

Supporters say he is unfairly victimised by left-wing judges who are out to get him, but critics say he has used his influence and wealth to dodge the law for many years.

Even if his convictions are upheld throughout the appeals process, Berlusconi is unlikely ever to see the inside of a prison cell.

Meanwhile the coalition cabinet is already riven with tensions and political analysts warn Berlusconi could bring down the government within months as opinion polls indicate that he would win fresh elections.