The head honcho of a $2.5 million methamphetamine ring in Hawke's Bay has been jailed for 13 years with a minimum non parole period of six and a half years.

Shane Thompson, 31, was described as the most comprehensive methamphetamine dealer Hawke's Bay has ever seen when he appeared in the Napier District Court this morning.

The Hastings man was the principal offender in the organised crime network taken down by a six-month-long police investigation last year.

The summary of facts stated he supplied 4.2kg of methamphetamine at both wholesale and retail level between November 2016 and September 2017.

When he was arrested police found a further 2.6kg for supply at the home of his co-offender, Petera Gamlen's, who stored bulk quantities of cash and methamphetamine for him.

Police found more than $130,000 in cash at Gamlen's house and $41,000 at Thompson's house.

Thompson constantly fielded calls or texts from lower level suppliers, who referred to each other by nicknames and used codes for quantities and meeting places.

Transactions were completed quickly so turnover was high; Thompson arranging for others to make the deliveries and receive cash.

As part of the police operation authorities retrieved text data and monitored phone calls.

In one conversation in June last year Gamlen told Thompson he had more than a kilogram of methamphetamine ready.

In another conversation between Thompson and another person in August Thompson told them he had 1.68kg ready.

At times purchasers came to Thompson's house and sometimes he made deliveries himself but he didn't like to keep supplies at his house so he stored the bulk of them at Gamlen's address.

He spent a lot of time out of town, often in Auckland where it was believed he sourced the bulk supplies.

Last year it was revealedThompson was a high-stakes pro gambler who went by the name of Shane Tamihana at New Zealand's richest poker games.

At sentencing this morning Thompson's defence lawyer Eric Forster said his client's offending may have given him readily-sourced funds to continue his gambling habits.

"What's really striking about Mr Thompson is he's a talent individual.

"If he puts his mind to something he's focused on it and does very well. He's competed competitively in sports of poker playing and done particularly well."

He noted Thompson had been largely raised by his father due to tragedy in his formative years and submitted his minimal criminal history indicated he was capable of reformation.

Crown prosecutor Clayton Walker submitted a starting point of 18 years, adding a minimum non-parole period was warranted given the seriousness of the offending.

Judge Geoff Rea began his sentencing by acknowledging Thompson was not addicted to the drug, and didn't even use it.

"It has to be said that the effects of the introduction of methamphetamine into this community as a result of you being at the head of this must have been significant and your overall profits would have been considerable."

He noted the "devastation" caused by methamphetamine in the Hawke's Bay community and others throughout the country, adding addiction to the Class A drug reduced people to deplorable life.

"All that put together makes you at least the most comprehensible meth dealer Hawke's Bay has ever seen and it puts you well up there on a national scale in the last 10 years as well."

Judge Rea said the Crown's starting point of 18 years was "generous" and, after discounts for his guilty plea and forfeiture of vehicles, sentenced him to 13 years with a minimum non parole period of six and a half years.

Excited whispers erupted from the public gallery as he was sentenced and his supporters made gang hand gestures and yelled 'Love you!' as he was taken away.

Judge Rea said Thompson's acceptance of his offending indicated he was capable of the reformation his lawyer Forster had earlier noted.

"One of the things that has struck me around this Mr Thompson is your ability and even willingness to accept your responsibility, not to push it off to anybody else..that shows a certain amount of character when faced with as sentence like this."

Thompson's second-in-charge, 30-year-old Petera Gamlen, was sentenced to 11 years and three months with a minimum non parole period of five years and seven months after pleading guilty to supplying methamphetamine, possessing methamphetamine for supply and the unlawful possession of eight firearms.

Thompson's girlfriend Nerrisha Marie Margaret Grant, 30, was sentenced to 12 month's home detention, escaping a jail sentence by a narrow margin, after pleading guilty to supplying methamphetamine.