Family mourn Melbourne mum killed by flying metal tool on freeway as police hunt driver

Police are searching for the driver of a truck after a metal tool fell from the vehicle and hit the windscreen of another car on a Melbourne freeway, killing a Deer Park mother at the wheel.

Mary-Anne Cutajar, 46, died when her sedan was struck by the metal tool near the Furlong Road exit in St Albans yesterday afternoon.

The mother and wife has been remembered by her family as a "beautiful soul" in the aftermath of her tragic death.

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Detective Sergeant Mark Amos said it was believed the metal object bounced over the freeway divider, landed in the Greensborough-bound lanes, and struck a sedan near the Furlong Road exit in St Albans about 4pm.

Images of the tool have been released in a bid to identify the white tray truck involved.

Cutajar, who was the sole occupant of the car struck by the object, died at the scene.

"Very sadly, as a result, the piece of metal penetrated the windscreen and struck the driver," Amos said.

"The lady sadly lost her life."

Police are still looking for the driver of the truck, who failed to stop and was last seen travelling Altona-bound on the freeway.

The piece of metal is believed to be a Riv-Nail Driver system, a specialised tool designed for maintaining conveyor belts such as those in the mining, manufacturing and food processing industries.

The tool is part of a system for installing rivets to securely fasten metal clips onto the end of conveyor belts.

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It is not known whether the driver of the truck knew what had happened.

"We have a minimum description of the vehicle, a white tray truck," Amos said.

"We need to try and find some answers for this poor woman's family because it's a really sad set of events and we want to work out why it has occurred and give some answers to (the family) who are sadly going to this year's Christmas minus one person.

"We need to take greater care, if you have a load on the trailer or a truck, just secure it. If you see debris on the roads, report it.

"We have to be responsible with what we do and until we start treating the roads with some respect, sadly I fear I will be doing this for the rest of my life."

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All Greensborough-bound lanes of the Ring Road were closed following the crash, sparking traffic chaos.

The roads have since reopened.