A father allegedly threw his four-year-old daughter off a bridge in front of the girl's two young brothers and scores of motorists during rush hour in Melbourne today.

Witnesses said Arthur Phillip Freeman, 35, suddenly stopped his family car – which also had his two young sons inside – and, with young Darcey Iris in his arms, walked to the side of the West Gate Bridge, just after 9 a.m.

He then allegedly dropped his young daughter over the railing and into the water, 190 feet below.

Shocked drivers who witnessed the incident – which police say occurred in a matter of seconds – immediately called emergency hotlines as Freeman reportedly got back in the large white family Land Cruiser, and drove away.

Darcey miraculously survived the fall and was pulled from the water by police within 10 minutes and ambulance officers spent the next 50 minutes resuscitating her on the bank on the side of the Yarra River.

She was then airlifted by helicopter to the nearby Royal Children’s Hospital in a critical condition and treated for the next four hours.

The tragedy gripped Australia as it unfolded on television, with footage of paramedics frantically trying to resuscitate Darcey on the riverbank streamed during regular news bulletins with updates on the little girl’s condition.

Freeman was arrested by police an hour after the tragic incident when he was spotted, accompanied by his two sons, Benjamin, 7, and Jack, 23 months, in a “visibly distressed” state outside the Commonwealth Law Courts across town in central Melbourne. The family had been in the midst of a custody battle.

Security staff at the court said that Freeman was shaking like a leaf, and staring with wild eyes when they spotted him and alerted police. Police, initially unaware he was involved in the bridge incident, said they took him into custody peacefully.

As he was being led away, Freeman reportedly begged court staff to "take care of my kids.''

“He was pretty down and he had the two other children with him and he tried to enter the court. He couldn't talk to anyone, he wouldn't talk to anyone, he was just a mess,'' witness Vince Mascia told the Nine Network.

As Freeman was being questioned by detectives, Darcey died in hospital from massive internal injuries.

Her father was then charged with murder and set to appear before a criminal court. However he was deemed "suicidal" by psychiatrists and remanded in custody. He will next appear in court on May 21 for a committal hearing.

Click here to read the full story from the London Times.