More than a dozen Vietnamese nationals on work visas are being investigated for links to an Auckland crime syndicate that was busted last week.
A multi-agency investigation uncovered the drug and money-laundering operation in Counties Manukau, police seizing cannabis plants and packaged cannabis with a street value of up to $25 million.
There were 10 arrests and 12 deportations. Most of the deportees travelled to NZ on visitor visas which had expired.
On Tuesday the Ministry for Business, Innovation and Employment said it was investigating a total of 15 people on accredited employer work visas, and whether accredited employers were involved. Of those, 14 were being investigated for potential deportation.
The ministry would not state the occupations listed on the visas of the 15 individuals due to the ongoing investigation.
"This operation was undertaken to disrupt criminal activity," a spokesperson said. "The visas the migrants were on in New Zealand are not relevant as the goal was to stop crime."
Police last week said some of the Vietnamese nationals came to New Zealand "specifically for the purpose of participating in these organised crime groups".
They primarily involved setting up "sophisticated indoor cannabis growing systems", police said.
"These arrests should serve as a warning to those that may be involved in these kinds of drug cultivation, drug dealing and money laundering operations, that police will hold them to account," Waitematā Acting Detective Sergeant David Coombridge said.
Further charges and arrests were not ruled out.
"We continue to encourage anyone with information about suspected money laundering and drug dealing in their community to contact 105, or Crime Stoppers anonymously via 0800 555 111," police said in a statement. "Migrant communities concerned with possible exploitation should contact MBIE on 0800 20 90 20."