There's a new currency operating in the country's prisons - nicotine lozenges.
Habitrol is at the centre of most of the fights one former prisoner saw during his time in four of the country's prisons, Waikeria, Spring Hill, Mt Eden and Christchurch.
The former inmate, who didn't want to be named for fear of retribution, said each smoker was given a box of habitrol when they first landed in prison, only for it to be taken off them by gang members once they got to their unit.
Corrections says it took reports of the standover tactics seriously and encouraged all prisoners falling victim to it to report the matter.
The inmate said he wanted to speak out now as he was both shocked and annoyed at the gangs controlling what happened behind bars.
If an inmate refused to hand over their lozenges, there would be a fight. It could escalate to involve a weapon or could be paid back by either money or the handing over of the prisoner's three meals for that day.
The lozenges were now dubbed "Corrections-made currency" by everyone behind bars, he said.
"These lozenges were introduced to help people quit it. Now they're known around the prisons as Corrections-made currency. That's what all the inmates call it.
"They're subsidised and paid for by the Government and now the gangs use them as currency."
Of the seven fights he saw during his stints behind bars, six were due to the lozenges.
"What shocked me the most was people who couldn't pay. They're not getting their food, their food is getting taxed and getting given to the person they owe.
"Even in segregation it was happening because the gangs sent prospects over."
He said nicotine patches were originally used as currency but then Corrections discovered inmates were making cigarettes out of them.
They were then swapped for the Habitrol lozenges which were currently being sold by gangs for $10 to $20 a box.
"You're given a box which has 18 trays of 12 in it and that's all you get. Especially if you've been smoking for 20 years, it's pretty hard.
"The moment you walk in the unit there's gangs waiting at the gate.
"You're walked in and it's pretty much 'Hand it over or you're gonna get a hiding'.
"If you want them they'll sell them back to you, but you've got to pay for them. At $10 to $20 a tray it adds up."
They get paid for at the P119, or on canteen day, when inmates get the chance to spend up $70 a week - of either their own money or that sent to them by family - on "junk food", including chips and lollies, but also phone cards.
He said Corrections officers turned a blind eye to what was happening, despite knowing the patches used to be an issue.
Corrections said it was concerned to hear reports of prison staff letting prisoners know of new arrivals who had lozenges on them.
"This type of behaviour is not acceptable, and, when we are made aware of such behaviour, we will take the appropriate action," chief custodial officer Neil Bates said.
He encouraged inmates to report abuses to Corrections staff, the Prison Inspectorate, the Ombudsman or their own lawyer.
"All matters will be treated seriously and, if proved, will result in the appropriate action taken against the perpetrator," Bates said.
He said Corrections staff worked with some of the country's most challenging people.
"Many resort to tactics including attempts to coerce, manipulate or intimidate staff and other prisoners to enable them to commit further crime," he said.
"This can include standover tactics on prisoners who they perceive to have something of value, such as shoes, CDs, food - and, in the years prior to the implementation of the Smokefree Environments Act, cigarettes."
Bates said prisons became smokefree on July 1, 2011.
To help newly arrived prisoners avoid sudden withdrawal from nictoine, each is assessed for their health needs.
They are then offered nicotine replacement therapy lozenges for a maximum of four weeks. That was based on health advice and the fact former smokers are not exposed to second-hand smoking exposure as they might be in the community.
Bates said each prison determines the best way to distribute the lozenges.
The inmate, meanwhile, suggested two ways to fix the problem; sell them at the prison canteen each week for around $15 which is what happened in Australian prisons.
"It's supply and demand ... if every one in the unit has got them then they can't make any money off them."
The other option was getting them dropped off daily by prison guards who locked each cell at night and did hourly checks.
"They come around when they lock everyone up at night and then come around every hour to do checks.
"Surely it will only take a couple of seconds to chuck one through your prison cell. It won't solve everything but I was just shocked over the amount of violence in prison over these things."
The former inmate said the "majority" of those who went to jail were smokers, meaning there was huge demand for the lozenges.