MILAN (REUTERS) - The collapse of a motorway bridge in Genoa in which 43 people died in 2018 was caused by a combination of factors, including insufficient maintenance, a report by technical advisers appointed by the judge in charge of the investigation said on Monday (Dec 21).

The 467 page report, seen by Reuters, said the main critical issues with the collapsed section of the bridge were design deficiencies in some details and execution flaws.

But the report added it was "surprising" how few inspections had been carried after 1993 on two pillars of the bridge, which was managed by Autostrade per l'Italia, the toll-road unit of infrastructure group Atlantia.

Autostrade per l'Italia declined to comment on the report.

During the bridge's lifetime no maintenance action aiming at arresting the deterioration process or fixing flaws has been taken, it said.

The Genoa bridge disaster caused a political storm around Autostrade and its parent Atlantia, controlled by Italy's powerful Benetton family, and the state of the motorway network it runs.

Atlantia is now in talks with a consortium led by Italy's state-backed investor Cassa Depositi e Prestiti over the sale of its 88 per cent stake in Autostrade.