Italian prosecutors are asking the courts to sentence a Malta-born Australian, 51-year-old Michael Calleja, to 15 years’ imprisonment for his involvement in a foiled shipment of cocaine from the Calabrian Mafia to Australia in 2004.

Calleja is among four Australian men who are being tried in absentia in Italy over drug smuggling. Calleja, of Kew, Nicola Ciconte, 54, Vincenzo Medici, 45 and Carmelo Loprete, 41, are being tried in Vibo Valentia in Calabria.

The four allegedly conspired with the Calabrian Mafia, the ’Ndrangheta, to ship some 500 kilograms of cocaine, with an estimated street value of $50 million, from South America to Melbourne through Italy between 2002 and 2004.

The plot was uncovered by the Italian police in an operation code named ‘Operation Decollo’, with the help of infiltrators in the international drug network

Calleja, Medici and Loprete allegedly made several trips to Italy to work out the details of their shipments.

Malta-born Calleja is said to have inspected the drugs and later was recorded telling Ciconte that the furniture was beautiful. Prosecutors also have photographic evidence of a meeting allegedly between Calleja and Medici with Mafia leaders.

Australia has so far refused Italian requests for the extradition of the four men.

The trial is the latest in a series of court cases to have emerged from the Operation Decollo investigation into a Mafia drug-smuggling network that allegedly sought to ship huge quantities of cocaine across four continents inside slabs of marble, plastic tubes and canned tuna.

Since senior Italian police and anti-Mafia investigators infiltrated the international drug network in 2000, a total of 119 people – both Italian and foreign nationals – have been tried and sentenced in Italy for involvement in the smuggling attempt.

The Australian Federal Police joined officers from the United States Drug Enforcement Administration and police from Venezuela, Colombia, France, Spain and The Netherlands to expose how the Calabrian Mafia used a sophisticated network to move cocaine around the world.