Updated Friday 2.15pm

A Gozitan woman has been killed in a freak incident on a Melbourne freeway.

MaryAnne Cutajar, 46, died when a ramp fell off a truck and struck her vehicle.

Cutajar, who moved to Australia 30 years ago, visited her home country just last month.

Australian media reported that, according to the police, a white truck was driving Altona-bound on the Western Ring Road at about 4pm on Thursday when the ramp came off.

The tool is believed to have come off the back of a truck on the M80, causing a fatal crash. Photo: Victoria Police

The ramp crossed into the Greensborough-bound lanes, striking Cutajar's car near the Furlong Road exit, in St Albans.

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

Inspector Craig McEvoy appealed to anyone who may have dashcam footage to supply it to police, and made a plea directly to the driver being sought.

"I'm hoping someone can now check the back of their ute, the back of their truck, or their vehicle in which they were carrying it," Inspector McEvoy said.

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 victim with her partner.

Her sister Antonella wrote on Facebook: "Please say a prayer for my sister Mary Anne, her husband, children and whole family."