Christchurch Police have arrested two men, after discovering 49kg of methamphetamine in a shipment of safety lights from Mexico.
Authorities say the drugs arrived by air on November 1, contained in 40 individual packages and worth more than $50 million.
The two men, aged 25 and 31, appeared in the Christchurch District Court on Wednesday, facing charges of importing a Class A drug and possession of methamphetamine for supply.
"These drugs, should they have made it to the streets, would have caused significant harm to people and communities, not just in Canterbury, but across the country," Detective inspector Corrie Parnell says.
"Methamphetamine is a destructive drug that wrecks lives, breaks down whanau and negatively impacts on our community."
Several search warrants were also carried out across Christchurch and Auckland, following the two-week operation between police and customs.
The pair are expected to reappear on November 20.