Three men have been charged after authorities found more than a quarter of a tonne of methamphetamine hidden inside an excavator sent from Hong Kong to Australia.
The 295kg illicit drug haul has an estimated street value of $184 million, authorities say.
Police raided four properties around Sydney on Tuesday and three men are facing possible life sentences after being charged over their alleged role in the importation.
The first of the trio, a 30-year-old Rydalmere man, will face court again next month.
His co-accused, a 25-year-old Merrylands man and a 26-year-old Prospect man, will face court in December.
Australian Border Force officers x-rayed the excavator when it arrived in July and detected "anomalies", Superintendent Graeme Campbell said.
Drug detection dogs also showed interest in the shipment and a further examination found metal boxes inside layers of concrete, steel and lead.
"It was a really clever concealment," Supt Campbell said on Thursday.
However, he reminded would-be importers the ABF and its partner agencies "can find these goods no matter how clever and imaginative these criminals are".
The drugs were removed and the excavator was delivered to its Penrith destination before being moved to Arndell Park two weeks later, where two men allegedly spent several days attempting to extract the drugs to no avail.
Australian Federal Police acting superintendent Luke Wilson said international groups were targeting Australia because the demand and prices for drugs were so high, with no sign of that changing anytime soon.
