A woman has died after a multi-car collision on the Monash Freeway, in Melbourne's south-east.

Six cars were involved in the crash near the Stud Road exit in Dandenong just after 7:30am.

A woman in her 50s died at the scene.

The woman was driving inbound when she has crossed over several lanes of traffic and hit a number of cars, police said.

No one else was injured.

Police said the exact circumstances surrounding the crash were yet to be determined but they believed she may have had a medical condition prior to the incident.

All inbound lanes along the freeway were closed at Stud Road but are now open.

Earlier this week two separate crashes involving motorcyclists saw significant lane closures and delays on the West Gate Bridge during afternoon peak.