Fire Rescue Victoria was called to an incident on Austral Place in Hallam at 7.55pm on Saturday 2 September following a Triple-0 call.
FRV was assisted by the Country Fire Authority, with 11 trucks and 44 firefighters attending and a ladder platform requested.
On arrival at 8.01pm, firefighters found an approximately 2000 square metre factory well alight and buildings on one side of the factory threatened by fire.
The fire was called under control 35 minutes later.
A community advice message was issued.
Energy Safe was notified as lithium batteries were believed to be involved.
The Fire Investigation Unit and Scientific Officer were also notified.