This combination of 12 file pictures shows Silvio Berlusconi gesturing in Rome. AFP

Silvio Berlusconi, the billionaire media mogul and former Italian prime minister who transformed the nation's politics with polarising policies and often alarmed his allies with his brazen remarks, died on Monday aged 86.

Berlusconi, Italy's longest-serving premier who counted Russian President Vladimir Putin as a friend and gained notoriety for his "bunga bunga" sex parties, had suffered from leukaemia and recently developed a lung infection.

He died at Milan's San Raffaele hospital, where he was admitted on Friday. Four of his five children and his brother Paolo were at his bedside, ANSA reported shortly before his death was announced. A state funeral will be held in Milan on Wednesday.

Backed by huge wealth and a media, real estate and football empire, Berlusconi launched into politics in 1994, upending traditional parties and becoming premier. Another businessman, Donald Trump, would mirror that approach in the United States two decades later.

Berlusconi's Forza Italia party is now a junior partner in Prime Minister Giorgia Meloni's right-wing coalition, and although he himself did not have a role in government, his death may bring fresh realignments in Italian politics.

His business empire also faces an uncertain future. He never publicly indicated who would take full charge of his MFE company following his death, even though his eldest daughter Marina is expected to play a prominent role.

PUTIN'S 'TRUE FRIEND'

Berlusconi's passing was mourned by political allies and rivals at home and leaders abroad, including Putin who said he was "a true friend. I have always sincerely admired his wisdom, his ability to make balanced, far-sighted decisions even in the most difficult situations."

That relationship was one of many from Berlusconi's colourful public and private life that caused a headache for allies and fodder for his foes.

Berlusconi refused to blame Putin for the 2022 invasion of Ukraine, saying Moscow only wanted to put "decent people" in charge. When Meloni was visiting Kyiv this year, she insisted Rome backs Ukraine regardless of remarks by any individuals.

On Monday, she said: "We fought, won, lost many battles with him, and also for him we will bring home the goals that we had jointly set ourselves. Farewell Silvio."

Enrico Letta, a former center-left premier, wrote on Twitter: "Berlusconi made the history of our country. His death marks one of those moments in which everyone, whether or not they backed his choices, feel affected."

Another former premier Mario Draghi, a non-partisan figure and one-time head of the European Central Bank, said Berlusconi "transformed politics and was loved by millions of Italians for his humanity and charisma."

SCANDALS AND CONTROVERSIES

After building a real estate, football and television empire in the 1970s and 1980s, Berlusconi threw himself into politics, becoming prime minister four times - in 1994-5, 2001-5, 2005-6 and 2008-11 - despite multiple legal scandals.

When he last stepped down in 2011, Italy was close to a Greek-style debt crisis and his own reputation sullied by allegations that he had hosted "bunga bunga" sex parties with underage women, something he denied. He was acquitted on appeal on all charges related to the parties, but he was convicted for tax fraud in 2013, leading to a five-year ban on holding public office.

Despite his health woes and the relentless court battles, Berlusconi refused to relinquish control of Forza Italia and returned to frontline politics, winning a seat in the European Parliament in 2019 and in the Italian Senate last year.

Perennially suntanned and vigorously promoted by his own media companies, Berlusconi brought his great skills as a salesman and communicator to the staid world of politics, offering a bright, optimistic outlook that voters lapped up.

His sense of humour often landed him in trouble, most recently in December when he told players of his Monza soccer team he would bring them "a bus of whores" if they beat a top Serie A rival. They went on to win.

Berlusconi is survived by his 33-year-old partner Marta Fascina, whom he called his wife despite not marrying her, two ex-spouses, five children, more than a dozen grandchildren and one great grandson.