Four men in Sydney and Melbourne have been arrested for allegedly importing 254kg of cocaine and 104kg of methyl-amphetmaine into Australia.
A 47-year-old Watanobbi man and a 75-year-old South African citizen were charged on counts of attempting to import and possess commercial quantities of the border controlled drugs.
Another 39-year-old Doonside man was charged with attempting to possess the drugs and a 38-year-old Roxburgh Park man also charged in relation to their import.
The arrests come as part of an investigation that was launched by the Australian Federal Police (AFP) in December into a suspected cargo of drugs concealed in mining equipment that was sent from South Africa to Melbourne.
AFP Commander John Beveridge said: "These arrests send a strong message to criminals who choose to import harmful drugs into our community for their own profits -- you will be caught, no matter how creative you believe your concealment method may be.
"The AFP will continue to work with its partner law enforcement agencies to disrupt all forms of drug importation attempts and target those who believe they are above the law."
Police allege X-ray images of the equipment found abnormalities in an iron ore extractor which were later to be revealed as 358 1kg blocks containing the drugs, according to a statement released on Friday.
The haul is understood to have a street value of approximately $186 million.
Three of the men were arrested in Sydney on February 5 after attempting to access the extractor, which had been delivered by police from Melbourne.
Further search warrants that were undertaken on the NSW Central Coast later led to the seizure of an undisclosed sum of money, which remains the subject of forensic testing.
A fourth man was later arrested in relation to the crime on February 8 in Melbourne.
The three men from Sydney appeared in Sydney Local Court on Monday and the fourth man appeared before Melbourne Magistrate's Court on Wednesday and all were remanded in custody.
The maximum penalty for this crime is life imprisonment.
The charges cap off a big week in illegal drug hauls after Federal police cracked a record $312 million cocaine bust on Monday and another 30-year-old Sydney man was arrested on Thursday in a separate incident where police seized 2.7kg of cocaine, approximately 15,500 ecstasy tablets, four hand guns and ammunition in Rozelle in Sydney.
The estimated street value of that haul was $5 million and sparked two further search warrants at homes in Rozelle and Glenhaven that later uncovered close to $300,000 in cash, 12.3kg of cocaine, 13.4kg of methyl-amphetamine, approximately 3.5kg of an unknown powder, jewellery, two handguns, a motorcycle and a Toyota Hiace van.
The man involved was taken to Surry Hills Police Station and charged with 15 offences including the supply of commercial quantities of prohibited drugs, the possession of an unregistered firearm, and not keeping a firearm safely.