Melbourne commuters are experiencing severe delays this morning after a truck rolled on the Western Ring Road.

The vehicle carrying scrap metal flipped over a concrete barrier before pinning a car at about 4.30am Tuesday. Neither driver suffered major injuries.

The crash occurred between Pascoe Vale Road and Sydney Road. At 8am one lane was still closed in each direction.

A lengthy clean up is expected to last throughout the peak morning period.

Cranes and heavy machinery will be brought in after traffic has eased to remove the truck and any remaining debris. This could potentially involve Altona-bound lanes being closed.

VicRoads is advising drivers that the freeway is still a faster option than alternate back street routes, but drivers are being advised to avoid the Western Ring Road where possible.