All those arrested were Vietnamese, police said.
OFCANZ has been working with New Zealand Police and Customs Service in partnership with the Royal Canadian Mounted Police and other Canadian authorities since the operation began in December last year.
The investigation was launched after Canadian authorities intercepted 6.6kg of methamphetamine concealed in truck shock absorbers which were destined for New Zealand.
It had a street value of NZD$7 million.
Police Minister Anne Tolley has congratulated police and OFCANZ on their "hard work and dedication" in tackling the drug syndicate.
"Methamphetamine is a horrendous drug, and this bust has the potential to stop many lives being destroyed," she said in a statement released today.
"The vigilance of our two countries has made our streets safer - there is no place in our communities for drugs."
Detective inspector Bruce Good of OFCANZ also said he was pleased with the operation.
"This has been another success for OFCANZ, Police and NZ Customs. It demonstrates our ability to co-operate extremely well at home as well as with overseas enforcement agencies. It sends a clear message to those attempting to bring drugs across the border that they will be apprehended," he said.
"I am particularly concerned about the safety issues we discovered at these grow houses and we've been working with electrical professionals in the termination phase of this operation."
The properties had all been modified internally without the consent of owners or agents and the electrical supply to the houses had been tampered with, Mr Good said.
"We've been dealing with live wires hanging loose, connections to the mains supply by-passed and houses left without any earthing mechanism. This type of tampering is potentially life threatening through the risk of either electric shock or fire."
Mr Good urged landlords to do regular and thorough checks on their properties.
- nzherald.co.nz
