The arrest of a fugitive Italian businessman with close ties to Silvio Berlusconi could cause new judicial problems for the scandal-plagued former prime minister, who is already on trial for corruption and paying for sex with a minor.

Valter Lavitola, publisher of a small newspaper and once a European Parliament candidate for Berlusconi's party, was arrested at Rome airport on Monday after eight months as a fugitive from justice in South America.

Prosecutors in the southern cities of Naples and Bari are investigating Lavitola and more than 20 other people on allegations including bribery.

Berlusconi, who was forced to resign in November, is not under investigation. But the case has turned the spotlight back on the former premier and media mogul.

Lavitola, 45, was an unofficial aide and fixer for Berlusconi and occasionally accompanied him on state trips abroad although he had no government role.

Naples prosecutors, who are due to interrogate Lavitola on Wednesday, ordered his arrest on charges of fraud connected to 23 million euros in public financing for L'Avanti, a socialist newspaper.

In another charge, magistrates also suspect Lavitola, who was looking after one of his business interests in Brazil when the arrest warrant was issued last year, acted as a middleman for the delivery of bribes by an Italian company to governments in Latin America.

Magistrates say he accompanied Berlusconi on official trips to Albania and Panama.

According to an arrest warrant by Naples prosecutors seen by Reuters, Lavitola was a state representative incognito whom Berlusconi trusted.

Before the arrest warrant was issued for Lavitola last year, Berlusconi and he spoke by phone and the conversation was intercepted by the Naples prosecutors.

During the conversation, which was leaked to the media, Berlusconi was purportedly heard urging Lavitola to stay outside Italy. Lavitola told the premier he was in Bulgaria.

MIDDLEMAN AND FIXER

In a separate case, prosecutors in Bari have linked Lavitola to a southern businessman, Gianpaolo Tarantini, who prosecutors allege provided high-class prostitutes for sex parties at Berlusconi's homes.

Lavitola denies wrongdoing, said his lawyer, Gaetano Balice.

Lavitola wants to clarify his position in the investigations involving him and to fully exercise his right to defend himself, Balice said.

In an interview with Corriere della Sera newspaper on the plane home, Lavitola said magistrates were coming after him because they didn't understand his relationship with the former premier.

Is it possible that Italian magistrates cannot yet understand that's the way he (Berlusconi) is? He likes to have a relationship with people like me, instead of with a queen or a president, Lavitola was quoted as saying.

Berlusconi, 75, was forced to resign five months ago as Italy risked a Greek-style debt crisis. His credibility had been undermined by reports that he had sex with an underage prostitute and regularly threw bunga bunga orgies with young women, including a member of his party elected to Lombardy's regional assembly.

At a hearing at the sex trial in Milan on Monday, a Moroccan woman, Imane Fadil, testified that the parties had involved young women, sometimes in pairs, stripping off nun's costumes during raunchy pole dances.

They started to dance like the nuns in the film 'Sister Act', and then they took off their clothes, she told the court.

During one of the parties, the girls provocatively showed Berlusconi their breasts and their bottoms, another woman, Melania Tupini, told the court.

Berlusconi is facing five criminal trials. The other four are on charges of corruption and tax fraud. He has always denied wrongdoing, saying he is the victim of politically-driven magistrates. He always maintained that parties at his homes were respectable.

(Additional reporting by Laura Viggiano; Editing by Barry Moody and Alessandra Rizzo)