There has been a major change in how international drug cartels are targeting New Zealand.
After years of Southern China being the number one source of methamphetamine smuggled into New Zealand, Customs say there have been no interceptions from China in 12 months.
Customs intelligence manager Jamie Bamford said it was likely there had been a "displacement effect" with narcotics made in China being smuggled through a different route.
Now, shipments from the Americas are registering at high numbers, despite two years of lower movements.
The total of drugs intercepted from North America were worth $23 million last year, but from January to August this year the worth rose to $114 million.
In South and Central America, the intercepted worth rose from $11 million in 2017 to more than $80 million in 2018.
"We play a game of cat and mouse with our adversaries, so I think we sort of block some channels and they look to push it through some others," Mr Bamford said.
Criminology professor Greg Newbold said some countries in the Americas "don't have such a big red flag attached to them", making it easier to import than from Asia.
To combat drug smuggling, New Zealand has posted top level investigators into key regions including China's Guangzhou, Hong Kong and Washington DC.
Mr Bamford said work in the US has seen the prevention of $45-46 million worth of drugs arriving in New Zealand.
"You can see there's a real effect."
Customs are set to establish a new post in Los Angeles in 2019 in response to the major increase in drugs from the Americas.