Most films have passed muster. On Jack's watch, only two cinematic releases have been banned: A Serbian film which featured graphic depictions of rape, necrophilia and child abuse, and Human Centipede 2, in which the central character tries to "sew" 12 people together. The latter was described by the Australian Film Classification Board, which also banned it, as "gratuitous" and "exploitative".
Seemingly random items such as drink cans and clothing are also required to jump through the classification hoops, the most memorable being the so-called Invercargill Hoodie, a sweatshirt from British metal band, Cradle of Filth, which bears Jesus' name and the C-word. The OFLC had previously banned it from sale in New Zealand but police later received a complaint that it was being sold in the deep south.
The bulk of contraband, however, tends to come from the office's work in classifying data files and hard-drives provided by the police, Customs Department and the Department of Internal Affairs as part of court prosecutions.
"These agencies provide us with often quite disturbing images of child abuse and pornography to classify for the purposes of investigation and prosecution. Either myself or my deputy will view them and make a decision."
There's much the 51-year-old sees on a daily basis that makes him feel ill. No amount of cajoling will, however, persuade him to provide specifics. But Jack reckons he witnessed much worse during his previous jobs with the police and Customs.
"At Customs we regularly intercepted very disturbing images, often of child pornography, being brought into the country. Some things can't be unseen and there are images that do stick in your mind, but you have to remind yourself you're there to do a job and you have to maintain a level of professionalism at all times."
Which is not to say the nation's moral gatekeeper can't be shocked, he's just had to become a little more thick-skinned. Jack is also big on the concept of "minimising injury to the public good and maximising people's freedom of expression".
"The Films, Videos and Publications Classification Act of 1993 sets out very clearly that in order to be deemed appropriate, material must not be injurious to the public good."
He uses those words a lot - injurious to the public good - but with good reason, because they're the cornerstone of censorship in New Zealand.
"We apply what we call 'gateway criteria' - sex, horror, crime, cruelty or violence - to material to determine if it's injurious to the public good. The legislation is clear on what we're looking for; for example, how violent the material is, how much is in context and how much is purely gratuitous? Is someone being shot from a distance or being disembowelled at close range? And is the activity being presented as normal or trivial and what message does that send?"
Artistic merit is also critical when walking the tightrope between freedom of expression and social responsibility.
"We want to determine if this is a story that needs to be told in New Zealand. Some films may be very violent or sexual in nature, but they can also have artistic merit or convey an important social message, and that's what we need to assess."
Different laws apply to different material: television and radio content are monitored by the Broadcasting Standards Authority, while books and magazines don't have to pass through the office unless they contain certain material - Penthouse and Playboy magazines, for example, are reviewed on an annual basis - or if a complaint is laid with the office, as happened with the recent best-seller, Fifty Shades Of Grey.
"I read it to ensure I was satisfied with its classification. And no, I won't tell you what I thought of it, because I'm not a reviewer."
About 15 per cent of videos and films - for both general release and film festivals - that enter New Zealand generally arrive at the censor's office if they carry an age restriction from either Australian or British censors or they are unclassified. They're screened at the office's eight viewing booths or, for mainstream releases, at early-morning private screenings at Wellington cinemas. "There will be two of us in a 300-person cinema," Jack says.
The other 85 per cent - films with G, PG and M stickers - come to the office's attention only following a complaint. This is unusual, but not unheard of: in 2007, for example, the office was forced to take action after receiving a number of complaints about the animated film Happy Feet.
"In Australia, it had a G rating but we received complaints that 7-year-olds were having nightmares because of a frightening scene featuring a sea lion. If we get enough complaints we'll reclassify the film. We watched it and didn't think it had been properly classified for a New Zealand audience so gave it a PG rating."
Jack isn't a man given over to excessive chest thumping, but believes the OFLC does get it right.
"The fact that our decisions are robust and balanced is reflected in the small number of complaints we receive. Probably the most complaints we've ever had was last year for the film Ted. It was R13 at the movies and out of 500,000 Kiwis that went to see it only 20 complained to us. So that tells me we're in touch with the public attitude."
To ensure it stays that way, his team uses a range of perspectives when classifying items ("for example, we'll have a 40-year-old white male and a young single female assess the same material," he explains), as well as meeting community groups and calling on experts when needed.
"We recently had to classify a film called My Suicide, about a young social outcast in California who decides to film his own suicide for a school project. It had real merit from an educational and social perspective but we didn't want it to encourage copycat suicides, so we called in experts from the Ministry of Health's youth suicide team to help us classify it."
Wouldn't it be easier to use the Australian classification system and save ourselves the bother?
"We do use it for unrestricted stuff but New Zealanders have their own attitudes, culture and national identity, which should be reflected in what we do and don't watch."
Besides, we don't tend to get our knickers in a twist about sex as much as the Aussies do apparently.
"Kiwis tend to be more comfortable with sex scenes than Australian audiences, while they have a higher tolerance of violence than we do. So what we might classify as an R16 or R18 here because of the level of violence might not get such a high classification in Australia."
It's quite a journey from the days when married couples on screen generally had to be shown in twin beds and one foot was required to remain on the floor in love scenes in case it harmed the nation's collective morals.
Certain words also used to cause headaches for censors, particularly when uttered in the presence of women. It's why the 1967 film adaptation of James Joyce's classic, Ulysses, which featured the F-word, was only permitted to be screened here if men and women were segregated on different sides of the cinema.
These days, the tsunami of sex, filth, cruelty and violence also arrives via new technologies such as computer games. To that end, the office has hired a part-time gamer to help them assess the complex and often inaccessible levels of games such as All Zombies Must Die, Redneck Redemption and Total Overdose. The criteria of the public good applies equally to gaming platforms and Jack says it helps that the industry enables classification officers to access the games' various levels.
Controversy is a frequent visitor. For example, the OFLC ruffled feathers with its decision that the Elijah Wood horror flick Maniac could be shown only at film festivals here (thereby preventing its later release on DVD), a decision distributor Neil Foley called "an insult to the intelligence of the adult population of New Zealand".
Jack knows he'll never top any popularity polls but, as you'd expect, he's firm on the need for censorship.
"These days, when it's easier than ever to access a whole range of films and videos, people need to understand what the potential harms of this material can be. A recent longitudinal study from the UK, for example, looked at issues with young male consumers of pornography over a 10-year period. By the time they were 25 these young men were less likely to be involved in a stable relationship, more likely to be earning less than their peers, more likely to have a complex relationship with women and more likely to resort to violence to resolve issues. It's something to be aware of when deciding what to consume."
So who is the man who gets to decide what you can and can't watch?
Jack was born in Howick, back when it was semi-rural and "Farmer Wilson used to walk his cows down the street for milking". His primary school teacher father was from Northern Ireland, his mother a radiographer who eventually became the oldest woman working in the field in New Zealand.
In different circumstances, Jack might have been a butcher: he slotted in a job at the local butcher's shop around his studies at Pakuranga College and was eventually offered a butchery apprenticeship.
Instead he chose the University of Auckland and a degree in "things that interested me", including the classics, Greek and law. He discovered a real aptitude for hieroglyphics and studied it to master's level.
Not everyone shared his passion, including the careers adviser who told him he should "jump out the window with those subjects".
Becoming a public servant was a more attractive option, so Jack moved to Wellington for 18 months. His year-long OE was spent mainly in Northern Ireland and Indonesia, after which he returned, determined to finish his law degree. That eventually morphed into a PhD, focusing on human rights in international broadcasting, a subject that has much relevance in his current role.
As befits our national arbiter of public taste and decency, Jack is a model of good taste.
Save for the black statement glasses, gold bracelet and trendy red string tied around his right wrist (a legacy of his wedding in Thailand), you'd be hard pressed to pick him out of an identity parade.
But he's good fun ("you need a sense of humour in this job") and is interesting because he's interested in almost everything.
He has five degrees and is part way through a quantity surveying qualification, does tai chi and adores his Harley Davidson almost as much as he does the three rescue dogs he and his wife Janette own.
After a hard day in the censor's office Jack does his own upholstery (the dogs keep eating the sofa), plays the bagpipes and dabbles in diamond grading.
And yes, he and Janette do go to the movies, mainly to see the unrestricted films his wife enjoys, such as last year's indie favourite, Beasts Of The Southern Wild. "I saw it at work and knew Janette would like it, so I paid to see it again at the cinema."
The term of a chief censor is three years and Jack's set to vacate next March. He won't say if he'll be seeking another term but does admit there's still much to be done, including reviewing the fee structure.
"At the moment distributors pay the same fee for classifying something like Avatar as they do for a small independent film festival movie. That obviously isn't fair and we're working on a range of options to try to address that."
And with that, he has to go. Someone, after all, has to watch the porn.
