It’s believed the two men were in a car that lost control near Keilor East before it started fishtailing, struck a pole, flipped over, and smashed into a railing.
Both men, from Truganina, were trapped for about two hours inside the crumpled black Mercedes sedan before paramedics could pull them free of the wreckage.
Ambulance Victoria spokesman John Mullen said the driver had injuries to his leg, while the passenger had abdominal and pelvic injuries.
Both men, aged in their 20s, were taken to the Royal Melbourne Hospital following the early Sunday morning crash.
One of them was still listed in a serious but stable condition on Sunday night.
The two men are members of the well-known western suburbs family, according to multiple media reports of the crash.
Victoria Police Sergeant Andrew Lawrence said detectives were still trying to figure out what led to the collision.
“Weather is obviously a factor,” he told reporters at the scene.
“It was raining at the time and we’re investigating whether speed was involved. We suspect it may have been.”
But a spokesperson for the Haddara family told Seven News that the car was not speeding and the driver was forced to swerve after being cut off by another driver.
Police said one witness left the scene before making a statement and should contact investigators as soon as possible.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at