Meth probably bound for Australia - expert

The meth had string for easy removal from the doors (Customs)
The meth had string for easy removal from the doors (Customs)

The biggest haul of methamphetamine ever seized by Customs could have been bound for Australia.

Ten shipping containers from China with bags of the drug welded into the door panels were intercepted at the border in July.

A 20-year-old Hong Kong man has been charged in relation to the smuggling operation, and criminologist Greg Newbold says Kiwi meth users probably weren't the target market.

The University of Canterbury sociology professor believes if that amount of P came onto the market here, the price of the drug would plummet and the smugglers' profits would go up in smoke.

"I would guess that some of it would have been shipped offshore," he told Newshub.

"I don't think Australian Customs would be particularly vigilant - they wouldn't expect to find a big haul of meth coming from New Zealand into Australia."

Customs only revealed the haul on Friday. It's Customs' biggest, but only half the amount police found in Northland in June. That was 494kg.

Prof Newbold said it shows our law enforcement agencies are staying a step ahead of smugglers.

"There's 1000 ways to smuggle methamphetamine - you can bring it inside the engines of cars, you can bring it inside artworks, you can bring it disguised as something else.

"New Zealand is hard though, to get stuff in, because we've got pretty vigilant Customs."