The system sounds simple enough. But the process, which is repeated regularly until the prisoner is freed or dies, is far more complicated for victims and their families.
Victims of each offender are invited to make submissions to the board on the prospect of parole and how it will affect them. The board is legally bound to consider each submission, but ultimately their job is to assess the offender.
In cases where there are multiple offenders, victims have to attend multiple hearings.
Leigh-Anne Mullins knows that all too well - and struggles with it.
Her father, Raymond Mullins, was murdered in 1999 by three teenage girls - Natalie and Katrina Fenton and their cousin Daniella Bowman.
They were sentenced to life in prison in 2000 for stabbing and beating the Papatoetoe engineer to death. The trio have had numerous parole hearings and been declined each time.
For Mullins the hearings have been too many and too often. Each time, she has to relive the horror of her father's murder.
She understands the parole board has a job to do, but feels that the system should be more victim-based.
Changes to the parole system announced earlier this year by Justice Minister Judith Collins and aimed at making life easier for victims, could help.
Those changes include pre-screening inmates to postpone unnecessary parole hearings and extending the maximum interval between parole hearings from one to two years.
The maximum postponement period for offenders serving indeterminate sentences and fixed sentences of 10 or more years would be extended from three to five years.
"Victims of crime will no longer need to face the very stressful prospect of parole hearings year after year, when an offender is clearly not safe to release into the community, and has made little or no effort at rehabilitation," Collins says.
Mullins says the changes would mean a "heck of a lot" less stress and trauma.
But she would still eventually have to face her father's killers and their bids for early freedom.
"It's horrible. I don't do it once, I do it three bloody times. I get the shakes, I get that awful sick feeling in the bottom of my stomach. My brain goes into overtime and it brings everything back about the day they killed my dad and they hell that we've been through since then," she says.
"It is very emotionally and physically draining. I don't think it's fair. But I've got to go for my dad. I've got to fight this until the end - and I will."
Mullins was stabbed 19 times, beaten about the head with a hammer and other weapons and left with the letter N or W carved into his chest.
Just 10 years later his murderers were eligible for release.
"I was horrified. Life should mean life. Victims never get released from this - I will never forgive and I will never forget, I've told the board that. The system is all for the prisoner. What does the victim get? I just can't get my head around it," she says.
"I understand how the system works, but coming up for parole so often is the worst part to deal with. It's like here we go again. And I've got to go and prepare myself again not just once, but three times."
Harwood has had some reprieve, with Holdem's parole hearings being postponed twice. But that doesn't make it easier.
On October 15, 1986, little Louisa Damodran, just days shy of her 7th birthday, was walking home from school and just 100m from home when Holdem - who was on parole after serving time for the 1982 attempted rape of a 10-year-old in a Christchurch park - kidnapped her. He drove her to the Waimakariri River, throttled her and drowned her. Her body was found downstream three weeks later.
Holdem was sentenced to life but became eligible for parole in 1996. He has been declined each time and Harwood has made a submission at each hearing.
He will appear again in April 2013 and she is already on tenterhooks.
"I have to emotionally bolster myself up for hearings. I want to be taken seriously, to get my message across.
"As Louisa's mother, it's my job to defend her and make sure no other child goes through what she went through.
"There is a lot of anxiety but I push myself to do it. It's usually scheduled around May and it means the entire month's kind of up-in-the-air. It's miserable. I can't sleep. In the middle of the night I started to feel guilty over him being kept in prison for 26 years. I've helped keep him from his own children ... I feel guilty about that. But I shouldn't.
"It's all a bit dismal. I'm just stressed all the time, preparing myself in case he gets out, preparing myself for the board, wondering if I am doing the right thing keeping him in there. And then I have to rehash it all every year ... It makes my life harder."
Mullins goes through "hell" at parole time. Being in Christchurch for a hearing in February 2011 has not helped matters.
"We'd just had the hearing for Bowman in Christchurch when the quake happened. It was so so horrific. Now every time I hear about the earthquake or an aftershock my body just shakes and all that comes flooding back to me. That's really taken a toll. It's another thing I'm a victim of that I shouldn't be ...
"The process re-victimises me. I don't, can't get over it. They took a life and nothing can change that. They can waste in there as far as I'm concerned."
The Sensible Sentencing Trust supports victims going through parole hearings. One of the main aims of the trust is to ensure violent offenders serve their entire sentence. Like Mullins, they believe "life means life".
Spokesman Garth McVicar, a relentless victim advocate, believes the current parole system is "barbaric" and hurts those it should be protecting. It's not fair on victims. In fact it's incredibly unfair," he says. "It's archaic what we do to our victims. It is modern-day torture.
He says watching people in the lead-up to hearings is "unpleasant".
"In some cases they've been able to put it away in a pigeon hole in their mind, they've been able to deal with it. But once a parole hearing is scheduled it brings it all up again.
"All that stress they felt at the time. It's like it was yesterday for them.
"I believe there's a real human impact, not just an impact on health but on the longevity of their lives. From what I've seen, from what I've experienced, I think parole hearings are the most unkind thing you can put people through, who have already been through the mill and back."
Mullins has attended every parole hearing for the three women jailed for killing her father. Each one turned her world upside down.
She says some hearings were pointless as there was no chance of the killers getting parole. Those "pointless" hearings were severely unfair on her and her aunt, who also went along.
"And at every hearing I remind the board of that - that I don't do it once, I do it three times. And for nothing."
Mullins says she suffers physically and emotionally in the lead-up and aftermath of the hearings.
"I get anxious. I lie in bed and I feel sick, it's like 'here we go again'. I go through what I've got to say, what I've got to do and worry that I won't be able to get it across.
"It just brings up everything again. I think, how am I going to deal with it this time? What am I going to say, what do I have to do to get it through to them that these girls shouldn't be coming out into society?"
Harwood has a history of mental illness and was in a Christchurch psychiatric unit at the same time as Holdem when Louisa was young. It's here that police believe he first saw the girl.
But the mental health issues she had before the murder don't compare to what Holdem's actions have put her through, repeatedly, since his first parole hearing.
"I have to keep him in prison until he dies. If he hadn't been given parole the first time, he wouldn't have killed Louisa. I think about that a lot."
Deciding whether killers like Holdem, the Fenton sisters and Bowman should get parole is no simple task. Before each hearing board members have huge amounts of reading to comprehend and consider, including the victim submissions.
The content of submissions is given due weight in the decision-making process, but the board is unable to simply do as the victim asks.
They cannot keep someone in prison - no matter how heinous their crime - if they are no longer a risk to society. They must be released.
Separate meetings are held with victims before the offender is heard. Board member Janice Donaldson has been part of those for the past decade. It's never easy, she says, and always fraught with emotion.
"I think we try to understand very much where they're coming from. The board tries very hard to be respectful of victims, to listen to what they have to say, and particularly when that addresses the issue of risk," she says.
"Submissions, whether they are written or we see the victim face-to-face, are of great importance to the board in making its decision.
"I'm always careful to go through all the submissions that victims have made so that I can say, what would this have been like at the time of the offending, so that I can place myself in the victim's position. Not in that way of feeling their emotion, but trying to feel some of what it would have been like. Obviously that's imperfect, it wasn't me in that situation. But, I consciously do that and I know a number of my colleagues do as well. We have a responsibility to the community and we take that very seriously."
For parole board manager Alistair Spierling, victim empathy is crucial.
"But we have to balance that with the board's function. The parole procedure is about the offender. The reality is we're not here to decide whether an offender has been punished enough. By statute, the offender is to be released and that can be quite difficult for the victims."
Spierling says parole is essential, that a system of managed release is five times more successful than if offenders are freed on their sentence end date with no possibility or consequence of recall. If you release someone at the end of their sentence with no recall, they are much more likely to reoffend. If we force someone to do their whole sentence - there is no incentive for them to progress.
"Research shows much more success doing it this way than the bods who serve X length of time and get turfed out. If you've no incentives the offender will come out of prison clearly no better than when they went in - but a bloody sight worse. That's the reason we have a parole system.
"We don't release them and say 'there you go, bugger off'. They are monitored and we can bring them back ... once a recall order is granted they are back inside until their sentence ends. For lifers, that's until they die.
"A life sentence means life. If someone is not safe they stay in prison. There is a misconception that a life sentence has a limit to it. It doesn't. There is no entitlement to parole, just an entitlement to be considered for it. They won't be left on the scrapheap, but it is possible they'll be in there for life."
Parole is decided on process - not what the board feels or thinks. It is up to them, says Justice Marion Frater, to analyse all available information, assess risk, and decide.
Despite the formulaic approach, that process is not easy.
"We are professional judges and that's the professional life. I won't say that we're not affected by it - of course you're affected by it. You wouldn't be human if you weren't affected," Frater says. "But we have to look at it dispassionately and apply strict decision-making processes when we come to reaching our decision."
It is natural for victims to want the offenders kept inside for their entire sentence. The board gets that, Frater says, and vows to do all it can to make the process easier for victims. But ultimately, they must make a decision based on more than what the victim wants.
"We understand that sentiment but that can't determine our decision."
Over the years Donaldson has seen a range of emotion, and dealt with the full spectrum of victims' expectations.
"It's always difficult. It makes the offending more real. We see the human emotions, we see the impact on people, we see the impact over time. You can't help but be moved by that."
She says the board is always clear and honest about what it can and cannot do for victims. Though there will always be those who do not like the end result, she wants people to trust that the board has done its job properly.
"I would like to think that they'd have faith in us to take into account the information that they have given us, and be confident that we have read it, that we have considered it carefully."
Ultimately, like many victims, McVicar does not believe in early release, essentially a reward for top-end offenders.
"They talk about the murderers who have successfully reintegrated. At what price? How many victims have taken their lives, had their lives destroyed, developed serious health problems?
"We release offenders ... why do we not throw the key away as a compassionate measure to victims?"
