Almost 500kg of meth has been seized coming into New Zealand, in Customs' largest-ever seizure of drugs at the border.

The drugs were hidden inside a shipment of electric motors that arrived at the Port of Auckland from Thailand in mid-August, a spokesperson for Customs said.

Two Canadians and a New Zealander are appearing on Friday in the Auckland District Court in relation to the bust.

They face charges for the important and possession of a class-A controlled drug, charges which carry a maximum penalty of life imprisonment.

The 469kg of meth has a street value of around $235 million.

The shipping container in which the drugs were hidden held 60 electric motors, with each motor concealing around 8kg of methamphetamine.

Customs said the shipment was assessed as high-risk based on an investigtion into an overseas criminal syndicate undertaken earlier in the year. The investigation then linked the syndicate to a New Zealand-based company.

"It’s a known international trend for overseas nationals to come into the country just to receive and distribute drug shipments," says Customs investigations manager Bruce Berr.

"They use storage units or commercial premises and hire homes on Airbnb as part of their illegal activity."

As part of the investigation, Customs and police continued to gather evidence to identify the people and companies involved in the import. This resulted in a number of search warrants being executed Thursday evening and Friday morning, said Berr. 

In those searches, a further 15kg of meth was found, along with a hang gun and a large quantity of cash.

"This seizure has disrupted a significant amount of drugs from reaching communities, and has deprived organised crime groups off hundreds of millions of dollars worth of profits."

Berr urged Air BnB property owners to "be alert so they don't unwittingly become involved in criminal activity".