Police arrested three people following a pursuit in Broadmeadows and surrounding suburbs on Thursday morning.
A 29-year-old female driver and two passengers were arrested at the scene about 12.45am.
It is alleged the female driver earlier dumped a stolen black Hyundai SUV on Tarella Drive, Keilor Downs before getting in a van and fleeing the scene.
Air Wing assisted police in following the van and stop sticks were deployed on the ground.
The vehicle came to a stop in Ardlie Street, Westmeadows.
Police searched the vehicles in both Keilor Downs and Westmeadows, and allegedly located a firearm and ammunition in the Hyundai and a quantity of drugs in the van.
A 29-year-old Lalor woman, a 30-year-old Prahran woman, and a 30-year-old Meadow Heights man are assisting police with their inquiries.