A man who played the role of "storeman" in an international drug ring has been sentenced to 10 years in jail after what the judge described as a "fall from grace".

Peter Dong Hae Kim received large quantities of methamphetamine, MDMA and cocaine from overseas and passed it on to others for delivery, including cash and weapons.

The 36-year-old was one of 10 people arrested in 2020 after an eight-month police investigation dubbed Operation Mystic, targeting what prosecutors called an "extremely large-scale drug importing and distribution syndicate".

Police had seized more than a tonne of methamphetamine, MDMA, cocaine and ephedrine worth some $5 million that was smuggled into New Zealand over three years.

Kim helped move at least 15kg of meth, 7kg of MDMA and two ounces of cocaine, Justice Rebecca Edwards said when delivering his sentence in the High Court at Auckland this morning.

Almost two dozen supporters including Kim's partner, siblings and friends sat in the public gallery for the hearing.

"Your offending comes as a shock to those who have known you," said Justice Edwards, referring to their letters describing the man as trustworthy and reliable.

Police seized firearms and ammunition along with $5 million of drugs in Operation Mystic. Photo / NZ Police

Originally from South Korea, Kim lost his mother when he was 12, one year after his family moved to New Zealand.

Other hardships in his life included a history of compulsive behaviours, and his father's strict discipline and alcohol use, the judge said.

Kim was running an internet cafe and working as a personal trainer when he became friends with a member of the drug syndicate.

The friendship would go on to feed a cocaine addiction that became the gateway to Kim's involvement in the group.

Kim's father died recently, the court heard, the stress of his son's arrest being a contributing factor.

But Justice Edwards said the defendant's cultural background could not be mitigating factors in his offending. "This is a fall from grace," she said.

Kim took directions from others in the syndicate and his primary motivation was financial reward, the judge said, although he showed no indication of living a lavish lifestyle.

She considered his offending less serious than others in the group but significant because of the sheer quantity of drugs moved.

He was sentenced to 10 years and 10 months' jail on three charges of possessing meth, MDMA, and cocaine for sale.

The sentence includes a 25 per cent credit for his guilty plea, and a further 10 per cent for remorse, rehabiliation efforts and low likelihood of reoffending.

She ordered a minimum period of imprisonment of 4 years and 4 months, citing the "irreparable and incalculable misery" that meth offending causes throughout the community.

"Not just those wrecked by addiction but also the victims of crime committed by the addicted," she said. "Your sentence serves as a deterrence for others."

Kim's court appearance comes almost three months after the sentencing of co-defendent Sam "Massive" Edmands, described as a drug addict who had a bit part in the scheme. He was sentenced to home detention.

Today's sentencing also comes 10 months after the sentencing of another co-defendant Mirtha Susan Ramos Mazuela - a dental hygienist originally from Chile who said she only participated in the drug trade to be closer to her son, Hugo Patricio Alarcon Ramos, who has been described as the syndicate's top lieutenant in New Zealand.

Mazuela was ordered to serve 11 years and six months in prison in July after pleading guilty to 12 charges involving importing, selling and possessing methamphetamine, cocaine, ephedrine and MDMA, as well as one additional charge of possessing materials for the manufacture of methamphetamine.

Her son was sentenced to 12 years in prison in September 2020.

Other co-defendants still await trial, including the alleged kingpin of the operation.

Additional reporting by Craig Kapitan