Italian police on Monday arrested the son of a powerful mafia "pirate" on charges of extortion, swooping in on him in a pub in a move described as a significant blow to the ruthless Casalesi clan.

Carmine Schiavone, son of the crime boss Francesco Schiavone -- nicknamed "Sandokan" after a fictional pirate of the late 19th century -- was tracked by police to a pub in Aversa, a town in the Campania region in southern Italy, and arrested after an hour-long chase through the streets.

Schiavone was carrying 8,000 euros ($10,600) in cash, which investigators said was either destined for mafia business or was money taken from local businessmen as protection money.

"You've done well," he told the police officers who caught him, according to Italian media reports.

"Sandokan", known for his bushy black beard and winning charm, was arrested in 1998 after police discovered his hideout behind a sliding wall of granite in his Naples villa, but still rules the Casalesi clan -- part of the powerful Camorra criminal organisation -- from behind bars.

Four of his five sons are serving time for crimes from mafia association to triple murder.

Schiavone's arrest is "a hard blow which we hope will be the final stroke and will convince those who pay protection money and are victims of extortion to speak out," said Michele Centola, head of police in Casal di Principe, where the Casalesi clan is based.