Italian state radio said the body of a 30-year-old man was found in rubble near the site, as three more bodies were found in a auto overnight.
It said they were three family members, including a child, who had been travelling for a holiday when their auto, with about 30 other vehicles, plunged when the bridge gave way.
Autostrade Chairman Fabio Cerchiai and Chief Executive Giovanni Castellucci held their first news conference since the disaster on Saturday in Genoa, as rescue workers kept searching for the last few unaccounted people buried in the rubble.
The Italian highway company in charge of the Genoa highway bridge that collapsed says it can build a new bridge in eight months.
Earlier reports put the number of victims at 41 people.
Italian newspaper La Stampa said many relatives had chose to snub the funeral and mass, believing the government bore some responsibility for the tragedy.
An 80-metre-long section of the bridge, part of a motorway linking the port city of Genoa with southern France, gave way in busy lunchtime traffic, sending dozens of vehicles into free-fall.
Victims of the Morandi Bridge disaster lie in coffins at the Fiera di Genova exhibition centre on August 17, 2018 in Genoa, Italy.
The archbishop of Genoa, Cardinal Angelo Bagnasco, presided over the solemn service.
"Today the government.has formally sent to Autostrade per l'Italia the letter of complaint that launches the process for revoking the concession", Prime Minister Giuseppe Conte said in a statement.
A relative holds a teddy bear as she mourns near the coffin of a victim of the collapsed Morandi highway bridge, prior to the funeral service in Genoa yesterday.
The motorway bridge in Genoa that collapsed killing 43 people is expected to take eight months to fix.
On Sunday, the government announced plans to check and fix Italy's motorways, bridges and viadicts, to ensure its aging infrastructure was safe.
Both the Sampdoria and Genoa teams had already announced they wouldn't play their matches this weekend but at a later date.
The dead also included children and three Chileans and four French nationals. The prosecutor investigating the bridge collapse has criticised past management of Italy's infrastructure.
The collapse has prompted fears over other aging infrastructure in Italy and overseas.
It denies scrimping on motorway maintenance, saying it has invested over one billion euros a year in "safety, maintenance and strengthening of the network" since 2012.
Atlantia, the holding company that controls Autostrade per l'Italia, had no immediate comment.The government is demanding that the company rebuild the bridge at its own expense and within a set period of time.
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