Police have discovered a large quantity of methylamphetamine as well as chemicals used to make drugs including ice, after raids in Newborough and Morwell on Tuesday.
It follows a six-month investigation into the manufacturing and trafficking of methylamphetamine in the Latrobe Valley.
"We're very satisfied that we've disrupted a very large supply of illicit drugs into the Latrobe Valley and Baw Baw communities," Morwell Divisional Tasking Unit Sergeant Brent Muir said.
Sgt Muir said illegal firearms and prohibited weapons were also seized from the Vasey Street, Morwell unit and a Newborough residential property.
A 50 year-old Newborough man was arrested at the Newborough property on Tuesday.
It is expected he will be charged later today.
Sgt Muir urged people with information to phone Crime Stoppers on 1800 333 000.