A joint operation between Customs and Police has intercepted New Zealand’s second-largest methamphetamine importation, hidden inside steel beams.

The agencies moved in on a rural Waikato property early on Friday morning, arresting two men from Australia who were in the process of dismantling the beams.

Customs had identified the concealment of 515 kilograms of methamphetamine within the heavy steel beams in early September, following their shipment from the United States. Customs’ intelligence work led to further scrutiny of the shipment, revealing inconsistencies in some of the 42 beams. Using x-ray technology and additional checks at the Sea Cargo Inspections Facility, Customs officers discovered the large quantity of drugs.

Under Operation Girder, Police’s National Organised Crime Group (NOCG) collaborated with Customs to identify those involved, executing warrants across Auckland and the Waikato in recent days. Five men, aged between 31 and 51, were arrested and appeared in the Auckland District Court on Friday, facing charges related to the importation and supply of methamphetamine. One man faces an additional charge for unlawful possession of firearms after a military-style semi-automatic rifle and ammunition were found.

The two men arrested in Waikato on 4 October hold New Zealand passports but live in Australia.

Detective Inspector Colin Parmenter, from the NOCG, said the seizure represents a significant disruption to the drug market in New Zealand.

“The significant amount seized in this operation is another demonstration of the Police and Customs partnership and commitment to the disruption and dismantling of transnational organised drug networks,” Parmenter said. “It’s estimated that this shipment would have gone on to produce 25.7 million individual doses of this destructive drug, and preventing this harm is a key motivation for our staff.”

He added that organised criminal groups seeking to profit from such activities remain a key focus for their resources. Further arrests have not been ruled out as investigations continue.

Customs’ Group Manager Intelligence, Investigations, and Enforcement, Terry Brown, emphasised the success of the operation in combating transnational crime.

“Customs’ intelligence gathering and targeting have played a critical role in detecting this smuggling attempt and identifying people responsible,” Brown said. “This joint operation has yielded intelligence that will lead to further enforcement opportunities for Customs and Police and has prevented more than $570 million in harm to New Zealand communities and our economy.”

Brown said the scale of the smuggling operation highlighted the lengths organised crime groups would go to, but the swift response from law enforcement showed their commitment to disrupting such efforts.

The public is encouraged to report any suspicions of smuggling to Crime Stoppers anonymously at 0800 555 111 or contact Customs confidentially at 0800 WE PROTECT (0800 937 768).