Prosecutors had sought a 10-year sentence for Giovanni Castellucci for failing to maintain a guard rail corroded by salt which allowed the coach to plunge 30 metres (100 feet) in one of Europe's worst road accidents.

"Shame! This isn't justice!" victims' relatives shouted as the verdict was read out at the courtroom in Avellino, Italian media reported.

The tourist bus, which was carrying around 50 pilgrims who had visited a Catholic shrine, rammed several cars after its brakes failed on a bend near Avellino, in the south, on July 28, 2013.

It then smashed through the safety rail of a viaduct and plunged into the void.

The court jailed several other people over the disaster, including the coach's owner Gennaro Lametta, for 12 years.

Lametta, the brother of the coach driver who died in the crash, was convicted of manslaughter and for lying about the vehicle's maintenance.

The court also jailed Antoinetta Ceriola from the Naples vehicle registration service for eight years.

Four local Autostrade employees were jailed for five years for negligence, and two others for six years.

The US-imported Jersey concrete barrier, corroded by salt used to keep the road ice-free in winter months, shattered on impact, leaving the bus to sail over the edge.

Autostrade, which runs almost half of Italy's motorway network, has come under huge pressure since a bridge it maintained in Genoa collapsed in August last year, killing 43 people.

Castellucci is under investigation for the collapse of the Morandi bridge, which had suffered from structural problems for decades, prompting severe criticism from engineering experts.