A large international police operation is unfolding across the North Island, targeting organised crime groups.
It is understood those involved have allegedly offended across borders of multiple countries.
Just before 9am, police confirmed a number of people have been arrested in relation to serious drug dealing and money laundering offences, a statement said.
They will appear in the Auckland District Court and Hamilton District Court this morning.
The exact number of people arrested has not been made known. However, some individuals are facing dozens of charges.
A 41-year-old Auckland man is due to appear in the Hamilton District Court this morning facing 68 charges ranging from money laundering to importing methamphetamine and class B drug MDMA.
His other charges include conspiring to import MDMA and conspiring to import cocaine.
The offences are alleged to have been carried out mainly in Hamilton or the Waikato are between 2019 and last month.
He also faces charges of supplying methamphetamine and MDMA.
One charge - on which he is jointly charged - relates to conspiring to import cocaine at Thailand on October 2 last year.
The money laundering charges relate to cash totalling more than $700,000.
Police are due to give an update on the situation at a press conference at 11am.
Police last night confirmed they were executing a number of search warrants at properties in the Auckland, Waikato, Bay of Plenty, Central and Wellington districts.
Australian media are reporting that the sting involved members of the Australian Federal Police working with overseas authorities, including the FBI, for up to three years.
During that time, they monitored a Trojan horse app dubbed AN0M that gangsters thought authorities couldn't tap into, Australia's Herald Sun reported.
"Police will allege senior Australian Mafia figures, feared bikies and members linked to South American drug cartels, Asian Triads and Middle Eastern and European criminal syndicates have been exposed by the sting - the largest in Australian history," the newspaper said.
Police have called a press conference in central Auckland this morning to discuss the "major trans-national organised crime operation".
A police spokeswoman told the Herald last night that the warrants are in relation to a National Organised Crime Group operation.
One of the warrants was believed to have been executed in Pt England last night, when a resident saw armed police on the street.
Later, a house was cordoned off and numerous police officers - some of whom were armed - could be seen outside.
A witness said a motorcyclist drove past the house at high speed, seemingly without noticing the police. The man then returned and parked his bike before going into the nearby dairy.
When he left he was spoken to by police and taken into custody.
The witness told the Herald he saw eight or 10 detectives at the house.
"They were just inside the address. I could see them walking around with gloves on."
Officers did not appear to be in a rush, he said, and no one was brought out of the property.
"I didn't see them take anything out [of the property]. But the lights were on. They were just moving around the house."
In West Auckland, locals in New Lynn said they had seen police around Rua Rd and nearby Croydon Rd.
"Saw two unmarked police cars on Rua Road today - two cops with assault rifles stood at the end of the driveway by the crossing."
A Herald reader also confirmed seeing a "huge" police presence in Albany between 4.30pm to 8pm yesterday, when a house was raided by officers.
"There were armed police vehicles and in total about 10 to 12 vehicles."
The reader said a number of Customs officials were also at the scene.
Residents in and around Whakatāne also reported seeing a heavy police presence in Ōpōtiki yesterday evening.
Staff at the News Whakatāne said they had received "multiple reports" of police there last night.
The Herald Sun said Australian authorities worked with the FBI to monitor the AN0M app that organised crime gangs used to plan executions, mass drug importations, industrial-scale money laundering and gun running.
Up to 4000 properties around Australia are said to have been raided by police.
Raids on AN0M users were carried out by authorities overnight - including in the US, the United Kingdom, Germany, the Netherlands and New Zealand.
Police told the newspaper that they foiled up to 21 murder plots and exposed the trafficking of billions of dollars worth of drugs into Australia.
More than 100 people have been charged, 3366kg of drugs and $35.8 million in cash seized, the Herald Sun reported. Up to 72 firearms were confiscated.
The whole operation to crack Australia's underworld has been dubbed worthy of a Hollywood script after it was revealed officers had managed to intercept, descramble and read a staggering 25 million messages sent on devices connected to the AN0M app.
An Australian Federal Police tech guru - described to be "unassuming" by the Herald Sun - hatched the plan over a few beers with FBI agents in 2018.
The AFP tech worker is said to have cracked the encrypted messages while sitting on the couch in the sitting room of his home in Canberra a few months earlier.
'We lost four days of work since we started work in this area, all because of rain.'