Police have seized more than 44kg of methamphetamine - half of which was concealed inside a bathtub - after searches across the Auckland region over the past two days.
There were 18 searches in the region, including in Ranui, Sandringham, Onehunga, Auckland CBD, Pakuranga, West Harbour and Wattle Downs.
Twenty one people have been arrested and face more than 200 charges relating to the importation of drugs, money laundering, and participating in an organised criminal group.
Police said they could not rule out further arrests or charges.
Nearly $1 million in cash, eight properties, a car park, and four high-end vehicles were also seized as part of yesterday's searches.
In a statement, Detective inspector Paul Newman said the assets seized were worth more than $10 million, which will be forfeited to the Crown's consolidated fund.
"This operation is all about preventing harm in our communities," he said.
"We have followed the money and it has lead us to substantial drug offending. Money has been their weakness; it is hard to conceal and our investigation has exploited this."
In an 11-month investigation dubbed Operation Worthington, police initially focused on a group of individuals allegedly laundering millions of dollars in cash, Newman said.
However, he said police soon found out the individuals were allegedly part of a wider syndicate involved in importing methamphetamine, along with other drugs such as ketamine and MDMA.
With help from Customs, a number of drug imports were intercepted and seized including a bathtub concealing more than 25kg of methamphetamine, police said.
A further 19kg of methamphetamine was also seized over the course of the investigation.
Police also seized 26kg of ephedrine and pseudoephedrine, and 5kg of ketamine and 3kg of MDMA.
Those arrested, aged between 19 and 43, are due to appear in the Auckland District Court.
$500m in cash and assets seized since 2017
Assistant commissioner Lauano Sue Schwalger said yesterday's operation highlighted the success of police's continued focus on organised crime.
"Police have seized a total estimated $513 million worth of cash and assets since the annual reporting target came into effect on 1 July 2017.
These include in Operation Frontia where assets were restrained and forfeited, including two boats and $28,700.
"Our goal was to hit $500 million by 30 June, and in doing so we know we have had a direct and significant impact on organised crime - an activity that feeds on greed, profits, and harm to the community."
In another operation this year targeting senior Mongrel Mob members, police seized $2m in cash and assets including five residential properties, vehicles, motorcycles, jet skis, cash and the contents of various bank accounts.
Black Power and Outlaws MC gangs were also targeted in another operation, where six people were arrested and firearms, methamphetamine, cannabis and synthetic drugs were seized.
Police Minister Poto Williams said gangs should not be making money from exploiting communities.
"This government is very clear - we will not tolerate organised crime and gangs and we are working hard to disrupt them.
"New Zealanders have the right to feel safe in their homes and their communities. Actions like this will go a long way to making New Zealanders safer by making a significant dent in the illicit economy which causes so much harm in our communities."
Officers last week achieved their largest ever forfeiture - worth more than $70m.
Crime proceeds are spent on community projects via the Proceeds of Crime Fund.