In a coordinated dawn operation, police stormed 60 clubhouses and properties simultaneously across Melbourne and its surroundings, following an escalating war between rival motorcycle outfits that has sparked a spate of shootings with high-powered weapons.
They seized guns, ammunition, explosive materials, drugs and cash.
The crackdown was launched after new anti-fortification laws came into effect on Sunday, which allow police to tear down barriers, cameras and booby traps at club facilities.
Thirteen people were arrested, including Hells Angels "sergeant-at-arms" Peter "Skitzo" Hewat. Fontana said the full extent of what had been seized would take time to determine as many of the properties were heavily fortified.
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But he admitted that none of the "high-powered military-style weapons" fow which police had been searching had so far been found.
"We're determined to track them down," he said.
"We've located a number of firearms, a large quantity of ammunition, we've located drugs, a large quantity of cash, but the investigations and searches are still going (on)."
Fontana added that police were "extremely concerned about these (high-powered) weapons", which reports said were AK-47s or M1 carbines.
"We're extremely concerned about the intel we've got about the tensions and the intentions of these clubs, and so we thought it necessary to make a pretty strong stance."
Recent incidents involving biker gangs in Melbourne have included a tattoo parlour being sprayed with bullets, makeshift bombs -- which did not explode -- thrown at a gym, and shots fired at a Hells Angels clubhouse.
As part of that pledge, new laws are being drafted in Queensland to ban motorcyclists riding in groups of three or more to stop them using numbers to intimidate, while 50 extra police have been put on Gold Coast streets.