The elaborate set-up in the former South Canterbury bank was capable of producing $800,000 of cannabis a year. Photo / NZ Police

One of the most sophisticated cannabis-cultivation cases police have seen has ended after five years with a green-fingered man behind bars.

Matthew Ian Anderson, 40, appeared in the Dunedin District Court recently where he was sentenced to three years and one month's imprisonment after a jury found him guilty on three counts of growing the class-C drug.

The protracted legal case began on February 22, 2017 when police raided a property in Temuka's King St.

The historic building, a former bank, housed a set-up that experienced police described as among the most complex they had seen.

A secret door inside the property's pantry opened out into the front of the building where five chambers had been constructed using timber and plywood.

Police seized 891 plants and 2.7kg of packaged product.

The place had been fitted with an elaborate heating, lighting, watering and air-filtering system which was capable of producing $800,000 of "very high quality" cannabis per year.

"There were several whiteboards on which a schedule and other data for growing the cannabis were set out, and other various pieces of equipment, including a trimming machine to remove leaves from stalk," Judge Michael Turner said.

The operation would have potentially cost hundreds of thousands of dollars to set up, police estimated.

Damian Richardson was living at the King St property and was initially the only one arrested.

Police also raided his mother's home nearby and found a "miniature version" of the grow in a container, housing 32 plants.

The court heard Richardson acted essentially as the caretaker at King St, living rent-free and being paid in product.

He was friends with Anderson and Timothy Snow, who previously socialised in the latter's "mancave", smoking cannabis.

"Mr Anderson held very strong views about the medicinal benefits of cannabis and the need for such cannabis to be of high quality," the judge said.

At trial, Anderson claimed he simply delivered items to King St but his co-defendants — who gave evidence against him — said his role was more hands-on.

He was the "mastermind" of the operation, Crown prosecutor Andrew McRae said.

By May 2017, police had found 67 seedlings and 1.5kg of the drug at Anderson's Geraldine home, all three men had been arrested and the long road to trial had started.

Richardson and Snow, however, both pleaded guilty and were last year sentenced to 12 months' home detention and nine months' home detention respectively.

After Covid-19 delays, appeals, lawyer unavailability, a mistrial and two failed attempts to have the charges dismissed, Anderson finally went to trial in Dunedin.

He remained adamant about the benefits of cannabis — describing it as the "miracle drug" — but now had a prescription to use it, the court heard.

In a letter, Anderson vowed never to fall foul of the law again.

Judge Turner, though, noted the man continued to claim he had been made a "scapegoat".

"While Mr Anderson may regret his actions, it is clear that he does not accept full responsibility for his behaviour."