Bomb Response Unit, Major Crime Scene and Arson detectives responded to a suspect package in Bayswater this morning, Victoria Police say.
At about 2.30am patrolling police spotted a parked Toyota Echo which was displaying stolen number plates on the Mountain Highway.
A man and a woman were initially seen with the vehicle however both had left the scene when police arrived to investigate.
The Bomb Response Unit conducted a controlled explosion just after 7am.
No explosive material has been found.
The package is no longer being treated as suspicious and the scene is being cleared.
Mountain Highway is now open.
A 21-year-old woman from Bayswater is currently assisting police with their enquiries.
The man is still is outstanding.
The investigation is ongoing and anyone with information is urged to contact Crime Stoppers.
