Three men were arrested at a rural property in Lara near Geelong on Tuesday as police uncovered 174 kilograms of ketamine, a border-controlled drug used by doctors and vets as a pain killer and sedative.
Australian Federal Police launched an investigation in late May after receiving intelligence from Spain's most powerful police force alerting its London-based officers to a suspicious sea cargo shipment.
The shipment of 360 buckets of liquid cement arrived in Melbourne from Spain on June 26.
It was examined by AFP teams and allegedly found to have about 80kg of ketamine within plastic tubes hidden inside about 40 of the buckets.
The shipment was delivered to a property in Merrimu near Bacchus Marsh on Tuesday, where it is alleged one of the men, a 33-year-old from Sunshine North, collected and transported the goods to the Lara property.
The two other alleged criminal syndicate members, a 37-year-old Altona man and a 32-year-old man from Hoppers Crossing, are accused of pouring out the liquid concrete to locate the illicit drugs when police pounced.
Another 80kg of suspected ketamine was later allegedly found buried in the ground at the Lara property.
Two high-powered gel blasters, about 25kg of suspected MDMA, roughly 14kg of suspected ketamine and an estimated $210,000 cash were also discovered in follow-up raids in Altona, Yarraville and Williamstown.
The 174kg ketamine seizure has an estimated wholesale value of $6.9 million.
AFP detective superintendent Anthony Hall said 40 people were admitted to hospitals in Australia every week as a result of drug use and the seizure would prevent significant harm to the community.
"Ketamine is a dangerous and illicit sedative," he said on Wednesday.
"Its dissociative effects block sensory brain signals and can cause memory loss, feelings of being detached from one's body and prevent their ability to perceive danger."
The three men are expected to face Melbourne Magistrates Court on Wednesday over a string of drug-related charges which carry a maximum sentence of life in prison.
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