Even as Silvio Berlusconi prepared yesterday to relaunch himself as a world statesman before the G8 summit, Italian prosecutors were suggesting that the Prime Minister could be questioned in a drugs and prostitution inquiry.

Mr Berlusconi will try to put two months of scandals behind him with a press conference today on a cruise ship off Naples to outline his agenda for the summit on July 8-10.

On Wednesday he is due to travel to Libya to meet Colonel Muammar Gaddafi, who made a controversial trip to Rome less than three weeks ago to seal accords on trade and illegal immigration.

However, prosecutors in Bari, in southern Italy, were reported as saying that he could be summoned as a witness as their inquiry continued into Giampaolo Tarantini, a local businessman at the centre of a scandal involving women sent to parties hosted by the Prime Minister.

There is no suggestion that Mr Berlusconi is under investigation in the drugs and prostitution investigation.

Summoning Mr Berlusconi to give evidence was possible, though “only a hypothesis at the moment”, Marco Dinapoli, one of the prosecutors, said.

Mr Tarantini, who rented a villa on the Costa Smeralda near Mr Berlusconi’s Sardinian retreat, the Villa Certosa, is said by police to have spoken to the Prime Minister “about 20 times a day” last year before and after the holiday of Ferragosto on August 15.

In the conversations Mr Berlusconi had described in detail the type of women he wanted at his parties, sometimes using “coarse language”, according to the magazine L'Espresso.

Several Italian newspapers — including Il Giornale, which is owned by the Berlusconi family — said yesterday that the inquiry had widened, with Mr Tarantini being investigated not only for “abetting prostitution” but also for allegedly dealing in cocaine. He denies both allegations.

Bari prosecutors are also examining statements made to police in Olbia, Sardinia, last summer by two unnamed women who said that they had “fallen ill” at Mr Tarantini’s villa, apparently after taking drugs.

The inquiry into Mr Tarantini’s alleged payments to women to attend Berlusconi parties in Rome and Sardinia was being widened to investigate the alleged recruitment of “foreign” women, reports said. Barbara Montereale, a model who attended Mr Berlusconi’s parties, has said that on one occasion at Villa Certosa she found several Slav or Eastern European women who “seemed to be at home there”.

Corriere della Sera published a letter on Saturday from Veronica Lario, Mr Berlusconi’s estranged wife, attacking “unwanted advice” over her decision to divorce him. The letter — her second to the newspaper — referred to an interview last week with Angelo Rizzoli, a friend of Mr Berlusconi since the 1970s, in which he described the divorce battle as having a detrimental effect on the couple’s children.

An opinion poll at the weeked indicated that the Prime Minister’s popularity had fallen below 50 per cent. It showed a sharp fall in support among women and young people, and especially among practising Catholics, with whom approval was down from 61 per cent to 54 per cent.

Mr Berlusconi also launched a package of anti-recession measures and advised those who were “negative” about the economy both in Italy and abroad to “shut their mouths” — a veiled comment to Mario Draghi, Governor of the Bank of Italy, who warned last week that the economy could contract by 5 per cent by the end of the year.

The Prime Minister said yesterday that he would invite reporters to attend his parties in future so they could “appreciate the quality of the shows”.

Prime Minister's questions

For weeks La Repubblica has printed ten questions for Silvio Berlusconi about his relationship with Noemi Letizia. Now it has updated them:

1 When did you first meet Ms Letizia? On how many occasions did you meet her? Have you ever consorted with underage girls?

2 What prevented you from telling the truth during the past two months?

3 Do you not believe that it is a serious matter, for Italian democracy and for your leadership, that you rewarded the girls who called you Papi with political candidacies and promises of political responsibility?

4 You spent the night of November 4, 2008, with a prostitute. According to magistrates’ investigations, dozens of call girls were brought to your residences. Did you know that these girls were prostitutes?

5 Have state aircraft been used to fly female guests to parties at your residences without you on board?

6 Are you certain that your relationships have in no way compromised affairs of state?

7 Would you still feel able to take part in Family Day or to sign a law punishing the clients of a prostitute? [Such a law has been proposed but delayed]

8 Do you believe you will still be able to stand for election as President of Italy?

9 Can you guarantee that you have never used, nor wish to use, the intelligence services or the police against witnesses, magistrates or journalists?

10 In the light of all that has emerged over the past two months, what is your state of health?

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