The alleged members of the notorious gang have been charged with a range of drug, firearms, weapons and explosives offences.

Police descended on more than a dozen addresses across Melbourne and regional Victoria, seizing guns, explosives, illicit drugs, prescription medication and cash.

"This is a group we know have traditionally been involved in violent crimes such as shootings, assaults, arson, drug trafficking, extortion and intimidation," Crime Command Acting Assistant Commissioner Mick Frewen said on Friday.

"In Victoria alone, the Mongols have been linked to a number of firearms incidents including multiple homicides and non-fatal shootings over the past 15 months."

The national operation called Task Force Morpheus involved local police, the dog squad, bomb response unit, AFP and Border Force and was designed not only to bring dangerous offenders to account but also to gather intelligence for future investigations.

A dozen Mongols bikies members were also served with firearm prohibition orders and police also did compliance checks on others already under the orders.

The arrests follow the seizure earlier this week of 12 guns from two patched members of the Mongols.

Police also searched a South Morang property in Melbourne's north, seizing a stolen Harley Davidson bike, drugs and ammunition.

There were also arrests in other states and seizures of firearms, drugs and cash.

Australian Associated Press