The 19th century saga of hard labour, solitary confinement and the lash is comprehensively explained, in detail and with some humour, by guides and in curated displays.

But if you're younger than 25 or have been hermetically sealed off from Australian history for the past 20 years, it's possible to visit and remain oblivious to its more recent horror.

The memorial garden dedicated to the 35 people murdered at the site on April 28, 1996 – then the world's worst mass murder by a lone gunman – is spare, beautiful and, if you don't know what you're looking for, easy to miss.

Shielded from the rest of the site by a row of native trees, it includes a reflection pool and the gutted shell of the Broad Arrow ​Cafe, where 20 people were killed in less than two minutes.

There is little signage, just the names of the dead on an elegant wooden cross, repeated on a stone, and some engraved poetry by the late Tasmanian writer Margaret Scott. A small plaque at one entrance has a short statement about the "devastating violent crime". There are few details and the gunman is not named.

As a place of quiet reflection, the minimalist approach works. The garden is deeply moving. But the discretion is not just an aesthetic choice. It is also a response to the needs of the historic site's nearly 200 staff, and the local community.

For 20 years, Port Arthur has struggled with how best to explain and mourn its modern-day history while straddling competing demands – protecting the deeply traumatised and informing the visiting public, who are often as curious and clueless about the massacre as they are about the convict experience.

Mostly, the site's management has put the people of Port Arthur – many of whom lost family members or friends and had their lives forever changed – first.

That low-key approach has been jolted in recent weeks by television specials and an influx of journalists. Next week, there will be the arrival of hundreds of guests and dignitaries, including prime ministers past and present, for a 20th anniversary memorial service. It has thrust the small community back into the national spotlight in a way, some locals say, it has not been since the immediate aftermath of the massacre.

For some victims' families and survivors, the service is a necessary recognition – and hopefully another part of a healing process. It tells them their loved ones mattered, and will not be forgotten.

For others, the national spotlight is re-opening wounds.

What is it like for a small community that continues to deal with the fallout – in post-traumatic illness, broken relationships and suicide – to again be made the face of an event so appalling that many would prefer to never speak of it?

Maria Stacey is one of a small handful of staff still working on the historic site from 20 years ago.

Now the site's visitor services manager, she says the anniversary is a time of mixed emotions for people across the Tasman Peninsula that surrounds Port Arthur.

"There have certainly been comments in the community made that you should just be forgetting about it," Stacey says.

"I have a good friend who lost a daughter, and she was confronted by a woman in the street who was saying just that to her: 'How awful it is that it is being dragged up, that you must feel awful about the service'. And my friend said, 'I'd feel more dreadful if there wasn't something, if it wasn't remembered'.

"That is what it is like – there are all sorts of different camps."

Reading the wishes of the community, the initial instinct of local authorities was similar to that of the woman in the street.

Stephen Large, chief executive of the Port Arthur Historic Site Management Authority, gave an interview in 2006 in which he said the 10th anniversary commemoration – with then prime minister John Howard as keynote speaker – would be the last on that scale. Since then, the moment has been marked quietly with the laying of a wreath and a minute's silence.

That plan held up until about nine months ago, when Large became aware of an expectation that there would be something more this year.

"I was contacted by a man who lost a close relative and wasn't ready to come to the 10th [anniversary]," he says. "He was pretty incensed when we said we weren't going to have anything, so we contacted some people who were closely affected and without exception they all said it would be a travesty if we didn't have a service," Large said.

"In hindsight, it really wasn't up to us or the [Tasmanian] government to make that decision, it's more for the people closely affected. It was pretty powerful stuff, so we made a decision really quickly."

The demand for a service was particularly strong from affected people not from the local district. The message for those who would prefer it wasn't happening has been gentle. As Stacey put it: "If people don't want to attend, they don't have to, but we decided it would happen for those who wanted it."

Large believes media interest in the massacre far outstrips that of a decade ago. Why?

Perhaps the massacre was fresher in the national mind then, and people didn't need or want reminding. The 10th anniversary service was also competing for attention with the Beaconsfield mine disaster, which was unfolding.

The recent push by pro-gun lobbyists to allow the use of the Adler A110 lever-action shotgun has helped thrust Port Arthur back into public consciousness. Howard has countered that the laws he brought in after the massacre should be strengthened, not weakened.

Whatever the reason, it has been a confronting time for those forced to re-live the past.

Channel Seven's Sunday Night, in particular, distressed locals by filming an actor with long blonde hair portraying the murderer, Martin Bryant, driving a yellow Volvo with a surfboard strapped to the roof near the historic site.

A woman living nearby assumed the production a crew were shooting a tourism film, and invited them on to her property for a better shot. She was stunned when she saw the Volvo doing laps outside her house. The re-enactment was later screened alongside previously unseen video of the police interview with Bryant.

Large was horrified. "Channel Seven was the first [program] that came out and it did rock a lot of people, and turn a lot of community members against doing anything," he says.

"I think they misrepresented to us what they were going to do in terms of filming on the site. We knew nothing about the police interview, and they certainly didn't say anything about the Volvo with the blonde man.

"I guess after that people got nervous and a bit disturbed that the media was going to just take us all back there."

To understand why this is such an issue, consider what seeing even a historic photo of Bryant means for locals, let alone catching sight of what looks like the killer driving outside your house.

Psychologist Rob Gordon, who worked on the recovery program after the massacre and returned to Port Arthur last month to speak with survivors, says being re-exposed to images or emotions such as those on Sunday Night can reactivate the trauma for those who were there.

"I was also incredibly disappointed by the recreation on [the ABC's] Australian Story," he says. "It's the ghoul factor – people who haven't had trauma like to be stimulated by others' extreme experiences – or at least Channel Seven thinks they do. But the graphic recreations are incredibly disturbing to people who were directly involved because it collapses the time scale between now and then."

Roseanne Heyward, the mayor of the local Tasman Council, backs this up. "When they show all that – when they show actual footage that was taken on the day, when they see that man's face and they see the shots being fired – it brings it all back," Heyward says.

"Someone who has there on the day said to me: 'When I see that, I can taste and feel that feeling that I had when I was there'. And [the anniversary] is not about that man. It's about remembering the people that were injured and died, and the people that were left behind."

Gordon says commemorative services can be important for survivors because they place the massacre as a historical part of their life story and allow it to recede into the past. It can help make some sense of what they have been through.

"The notion of recovery doesn't mean getting back to the way things were before, because they're never going to be the same again. The whole task of recovery is about establishing a new world, a new order, a new normality," Gordon says.

"Sadly, there is often very little understanding of that amongst people whose friends and family haven't experienced trauma."

In the early days, after Bryant pleaded guilty and when nearly everyone at Port Arthur was in a deep state of trauma, visitors who asked about the shooting were given a booklet with the full transcript of his Supreme Court sentence hearing.

After a couple of years a decision was made to pull back, out of respect to the survivors and staff. By then, travel guides such as Lonely Planet were advising visitors not to ask questions about the shooting. Those who did ask were quietly given a new, less detailed, brochure.

A decade-and-a-half on, that approach largely remains. Guided tours now include a brief nod in the direction of the former Broad Arrow ​Cafe, but little more.

Stacey says some visitors to the site react angrily to the lack of information, but there has been good reason for it.

"The reality is we still have people who work here who were there on the day at the time of the shooting," she says. "There are also people who came to work here soon afterwards, and even people who came weeks and months and years after who are affected by what happened," Stacey says.

"Out of courtesy to them in the workplace, we really don't want them to be asked questions that might cause them to burst into tears."

But she supports Large's view that the Port Arthur community is ready for a different approach, and that it is time to tell the story of 1996 in greater depth. Large says: "We've got to recognise that it's now part of the site's history, as unfortunate an incident as it was, and I think one of the things we're looking at over the next 12 months after the anniversary is over is how we can do that better."

The Tasman Peninsula was hit hard in the years after the attack. The historic site – the region's biggest employer by some distance – was closed for an extended period after the shooting and when it first reopened a spooked public stayed away. The local economy crashed, businesses closed. Many people moved away.

But in recent years there has been recovery. Visitor numbers at the site have been propelled to record levels on the back of world heritage listing in 2010, and the surge in tourists coming to Tasmania following the opening of David Walsh's Museum of Old and New Art. The creation of the 68-kilometre Three Capes bushwalking track through nearby pristine wilderness has brought a new type of visitor to the area. Earlier this month it was announced a luxury resort would be built behind the historic site, reflecting increased demand.

Gordon talks about the need to create a new, positive story to help deal with trauma, and this is what the peninsula has been doing.

As mayor, Heyward says there is a good story to tell, beyond the glare of the coming week.

"Hopefully after the service is done we can get back to our lives, there will be no more calls from the media and we can move on," she says.

"Who knows what will happen in 10 years time? I definitely won't be saying we won't be doing this again. But it is only a part of who we are."

Adam Morton is on Facebook and Twitter