Consumer group Adusbef said in a statement a judge had asked for the case to go to trial, adding a court hearing will take place on July 11 2013.

It said the proceedings centred around six derivative products sold to the city council of Acqui Terme, in the Piedmont region, between 2004 and 2006.

In an emailed comment, UniCredit said it was convinced it had committed no irregularity.

"...(We) trust that in the courtroom it will emerge that the accusations are unfounded," the bank said.

It is the latest in a series of legal cases pitting cash-hungry Italian local authorities against domestic and international banks over complex financial deals that turned sour.

The Italian Treasury estimates around 600 local authorities in Italy have bought around 36 billion euros ($46.39 billion) in derivative products.

In the most high-profile case to date, Depfa Bank, Deutsche Bank, JPMorgan and UBS are currently embroiled in a court case over the sale of derivatives deals to the city of Milan. The banks deny any wrongdoing.