Alleged drug smugglers accused of bringing millions of dollars' worth of cocaine from Colombia into New Zealand allegedly have direct links to the feared Medellin cartel, it's understood.

Police say eight people have been arrested as part of a joint National Organised Crime Group (NOCG) and Customs sting dubbed Operation Mist.

National Organised Crime Group director Detective Superintendent Greg Williams and New Zealand Customs service manager for intelligence Bruce Berry spoke at a press conference in Christchurch this afternoon.

Bundles of cash in $50,000 stacks, along with blocks of cocaine on scales, and items that the drugs were allegedly transported in were shown to the media on a large screen.

Greg Williams. Photo: George Heard

About 50kg of cocaine had been seized either in New Zealand or at overseas ports after a 10-month probe.

There had been six search warrants carried out in Canterbury, with six Colombian nationals and one Argentinian arrested.

One person had been arrested in Auckland.

The joint operation working alongside the DEA, Colombian national police, Spanish customs, and Cook Islands customs service.

Williams thanked the DEA for providing a lot of resources in the case - as well as the police in Colombia.

It was a massive blow to the organised crime group and the flow of cocaine in the country.

Some of the items found in the bust. Photo: George Heard

Consumption of the drug is relatively low compared to other countries.

This particular group was one of the significant suppliers of cocaine into New Zealand.

Networks from Colombia brought the drugs into New Zealand, with money going to the US.

Around $300,000 in cash has been seized, along with crypto wallets.

At least $600,000 had been laundered.

Williams said that they were a significant well-oiled group who tried to push the money out of the country as quick as they could.

New Zealand was being targeted by organised crime because Kiwis pay some of the highest prices for illicit drugs in the world.

Vast profits were available to the gangs, he said.

And now they are inserting their own people into New Zealand and getting supply lines with locals gangs and organised crime.

Twenty-three of such drug smuggling cells have been smashed around the world over the last few years.

The groups are intent on pumping "massive amounts" of cocaine, MDMA, and meth which is causing widespread social harm, Williams said.

But the gangs are not taking into account that New Zealand has good capability and legislation, with support from international partners, and knowledge of the networks and "who's who in the zoo"

The message today for the cartels, Williams said, is: "Don't bother coming."

Operation Mist is another example of strong relationships between NZ agencies and international partners to disrupt organised crime, Williams said.

Berry said Customs and Police are constantly trying to disrupt smuggling rings.

The problem is not going away and the lucrativeness of the market makes NZ an attractive target.

A common method of getting the drugs into New Zealand was hiding them inside other things and putting them on shipping containers.

A heat exchanger, for example, had around 1kg of cocaine hidden inside it and was discovered this month.

Large pieces of machinery, sweets or lollies, the gangs were try and concealing drugs in all sorts of things.

Williams was reluctant to go into details of the networks involved in Colombia.

But "key people in Colombia" have been identified, he said.

Although eight people have been arrested, and phones have been seized, the police are looking at who else is involved. More cocaine could still be en route, from this group, and will be seized by police, Williams added.

The Herald understands that police will allege links to the Medellin cartel, founded and led by Pablo Escobar.

"Two appeared in the Christchurch District Court yesterday afternoon facing serious drug charges," a police spokeswoman said.

Four foreign nationals involved in orchestrating the smuggling of $20 million worth of cocaine into Tauranga, the biggest cocaine haul destined for the New Zealand market, were jailed last year.

Croatian Mario Habulin, 48, Serbian national Deni Cavallo, 48, and Australian nationals Matthew John Scott, 46, and Benjamin John Northway, 37, were all sentenced in the Rotorua High Court, receiving sentences between 14-and-a-half years and 27-and-a-half years.

In May 2016, 35kg of cocaine arrived in New Zealand inside a diamante-encrusted horse head statue, which arrived by plane from Mexico via Hong Kong.