Other images showed a green truck that had stopped just metres short of the gaping hole in the bridge.
Transport Minister Danilo Toninelli called the incident "unacceptable" and said "whoever made a mistake must pay" if negligence is found to be a factor in the collapse.
The condition of the bridge, and its ability to sustain large increases in both the intensity and weight of traffic over the years, have been a focus of public debate since Tuesday's collapse, when an 80-metre span gave way at lunchtime as cars packed with holidaymakers as well as trucks streamed across it.
Firefighters searched into the night for survivors and bodies amid the rubble of the collapsed bridge which so far has led to the deaths of at least 26.
Asked about the collapse on a live broadcast, Mr Salvini responded: "We should ask ourselves whether respecting these (budget) limits is more important than the safety of Italian citizens".
The tender provided for a strengthening of the bridge's pier cables, including those of pier nine, the one that collapsed on Tuesday.
Fellow deputy premier Luigi Di Maio, who is expected in Genoa by 1100 (0900 GMT), said the tragedy "could have been avoided", adding that those responsible for the disaster had a "name and surname".
"I'm following with great apprehension what has happened in Genoa, which appears to be an enormous tragedy", transport minister Danilo Toninelli tweeted.
But the head of the civil protection agency, Angelo Borrelli, said he was not aware that any maintenance work was being done on the bridge.
On Tuesday specialist engineering website Ingegneri.info published a piece that highlighted how the bridge had always presented "structural doubts", calling it "a tragedy waiting to happen".
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Between firefighters police and other emergency service, around a thousand people have been mobilised in the rescue effort, according to the Civil Protection service.
The Red Cross reported that 11 people had been rescued from the rubble alive.
The Italy built in the 1950s and 1960s is in urgent need of renovation.
Atlantia and Autostrade per l'Italia could not immediately be reached for comment. But Stefano Marigliani, the motorway operator Autostrade's official responsible for the Genoa area, told Reuters the bridge was "constantly monitored and supervised well beyond what the law required".
The design of the bridge has been criticized in the past. "But there will be a time when the cost of maintenance will be higher than a replacement", he told Italian media Primocanale.
Autostrade said it would work with investigators to discover the cause of the disaster, and that it was already assessing how to rebuild the bridge.
"This bridge has had quite a lot of maintenance work", said Ian Firth, past president of the UK-based Institution of Structural Engineers, and a structural engineer specialising in bridges.
Restructuring work on the bridge was carried out in 2016. The motorway it carries is a major artery from northern Italy's industrial centres to the Italian Riviera and to France's southern coast.
A former goalkeeper for Italian Serie A club Cagliari survived the deadly collapse of a motorway viaduct in Genoa on Tuesday despite going down with the bridge in his vehicle and finishing among the rubble.