Police have slapped 10 people with more than 130 charges and discovered a massive haul of weapons in the aftermath of a robbery in Melbourne.

As part of a months-long investigation, detectives uncovered a military mortar shell at parkland in Mount Waverley and came away with 22 guns, five imitation firearms, gun parts, ammunition, explosives, an electronic jammer and knuckle dusters following raids in Melbourne’s north and southeast.

They also found drugs including GHB, LSD, methylamphetamine and cannabis, pepper spray, 3D-printed gun parts, stolen property and cash during the raids – some conducted on several homes and a storage facility on Thursday afternoon. 

The alleged discoveries form part of officers’ investigation into an armed robbery at a licensed premises on Dandenong Road at Mulgrave on November 3.

Two men armed with handguns demanded cash from staff at the venue and left with a small amount, fleeing in a waiting vehicle, police allege.

Staff and patrons inside were uninjured during the incident.

Officers initially raided addresses at Oakleigh South, Clayton South and Highett on November 21 and arrested three people including a 28-year-old man who was charged with offences including possessing an unregistered handgun and ammunition.

He was remanded in custody to appear in Melbourne Magistrates Court on February 18.

Another 29-year-old man was granted bail to appear at Moorabbin Magistrates Court on February 28 while a 31-year-old woman was expected to be charged on summons.

A further raid on January 8 led to another 27-year-old man’s arrest, while Thursday’s raids led officers to arrest seven people overnight.

Among the group, a 29-year-old Clayton South man was charged with almost 40 firearms and drugs offences and a 30-year-old man from the same suburb was charged with 25 gun offences.

Another 29-year-old Keysborough man was charged with 30 offences related to guns, drugs and stolen goods.

Armed Crime Squad Detective Inspector Mark Hatt said the seizures showed officers would target people who illegally had guns.

“This is a clear message to anyone illegally carrying firearms – we will track down and charge those involved in the manufacture, trafficking, and use of illicit firearms,” he said.

“We will continue to work tirelessly to prevent the access and use of illicit firearms, particularly by groups and criminals involved in serious and organised crime.” 

–AAP