Authorities seized six kilograms of methamphetamine with a street value of approximately $6 million, Williams said.
The four were charged in September 2015 and have now been convicted.
A 24-year-old man and 27-year-old woman, both New Zealanders of Taiwanese descent, were convicted of one charge of conspiracy to import methamphetamine, and one charge of conspiracy to supply methamphetamine. Each was sentenced to nine years in prison today.
A Taiwanese man, 25, was convicted on three charges of importing methamphetamine and one charge of conspiracy to import methamphetamine and sentenced to 19 years in prison.
A second Taiwanese man, 21, was convicted on one charge of conspiracy to import methamphetamine and sentenced to six years in prison.
Williams said the investigation and subsequent convictions "reflects the effectiveness of joint agency co-operation in detecting and dealing with this type of offending".
"Police are under no illusion that there is a very high demand for this drug. The damage to individuals, families and whanau from methamphetamine is immeasurable.
"Our work to disrupt these organised criminal groups who do not care at all about the devastation this drug causes to our community is ongoing."